Internal Medicine

One of the limiting factors in effective medicine has always been a lack of full understanding of the intricate processes which take place inside the human body, and our inability to manipulate the microscopic objects that may lie at the root of the trouble. An obvious solution, from a science-fictional viewpoint, is to seek out such knowledge firsthand - through miniaturisation of one or more scientists or medics [1]. Here I take a look at the surprisingly extensive narratives of miniaturised adventures within the human body - internal medicine.

Early Voyages

 While the minds of most readers will have jumped straight to the massively influential 1966 film Fantastic Voyage (on which more later), examples of the same basic premise can be found much earlier.

Perhaps the earliest science fiction narrative to explore the human body in all its detail from the inside was a novella called The World Inside by Joe W Skidmore, published in two parts in Wonder Stories, Feb & Apr 1936 [2]. The protagonist of this story, Donald Millstein, is a classic pulp science fiction hero: rich, morally superlative, in perfect physical health, and explicitly described as “the bravest, smartest, and most resourceful man in all the world”. His arch enemy, a mad physicist who goes by the sobriquet The Falcon, tries to have him murdered, only for Don’s fiancé Joane to fling herself in front of the bullet. Don and his surgeon friend Mado promptly make use of his newly-invented Atomic Reducer to perform microsurgery at the injury site. The miniaturisation device changes the strength of the electromagnetic fine structure constant to pull electrons into tighter orbits and so reduce the dimensions of atoms, and was intended for research:

“man will learn the truth about microbe life! Even the untold secrets of cell life—of the amoeba—will be as an open book. Perhaps, even the secret of life may be solved!”

Since the compressed atoms would mean a greatly increased density, Don must incidentally also invent gravity nullifiers to adjust the weight of anything reduced.

As an editor’s note on the second half informs us,

Skidmore has spent twenty years in the study of chemistry, micrology, and the other sciences used in this tale and has submitted to us a list of authoritative books he has referred to. While there is plenty of good science here, we do not want you to think that it reads like a text-book—far from it! Most of the time you will not even be conscious of the instructive facts offered you in “sugar-coated” doses.

As might be expected after the endorsement, given the time at which it is written and setting aside the unexplained technology and a fair bit of artistic license, aspects of the core science are fairly accurate. Don and Mado only see in the ultraviolet (due to the tiny lenses and retina in their eyes), and observe a number of robust scientific processes such as mitosis, healing and immune reactions, in an environment which is described as resembling a dense jungle. Of course, there are bizarre elements: most of the germs and bacteria (such as trypanosomes, spirochetes, gangrene bacillus and others) found in the body are given animal forms, complete with limbs, heads, eyes, pincers and fangs (as shown in the picture). The red blood cells (given their proper name of erythrocytes) are described as spheroids rather than disks and, more oddly still, release breathable air when they are punctured like little balloons (rather than having oxygen tightly bonded to their haemoglobin molecules, as we now know to be the case). Don and Mado deal with this inner life primarily with swords and axes, in a series of melodramatic life-and-death battles, although they also lure a number into the grip of white blood cells (leucocytes) which devour them. These, of course, also present an existential danger to the two micro-surgeons:

The great leucocyte, which appeared as a vicious ten-foot globe of evil life to Don and Mado, swiftly changed its devilfish-like body to a shape like that of a huge menacing umbrella!

Ultimately the surgery is successful, and the two make an egress through Joane’s throat.

Such microscopic medicine features in several other narratives [3] but wasn’t the only motivation for expeditions inside the body in science fiction.

Another early pulp SF novel of note to explore the body from the inside is The Bridge to Earth by Robert Moore Williams, which appeared in Startling Stories in September 1939. In this story, the protagonist John Dark tries to foil an alien invasion of Earth. The methodology of the invasion is miniaturisation: through the connivance of a human ally, the aliens are reduced to microscopic size and injected into people, taking control of their bodies through tapping nerves, often resulting in a spontaneous combustion which becomes known as a plague of Flaming Death. Dark is the only one to understand its origins, and, in disguise, joins one of the invading parties:

In less desperate circumstances, he would have welcomed the opportunity to take advantage of the marvellous chance for discovery the Marling reduction process had given him. He could do things that no surgeon had ever been able to do, observe the actual operation of the human body, the bewildering complexity of nerve and muscle action, the operation of the glands, the functioning of the ductless system.

Dark had no time for study. He had to get out. Once out, he had to devise some method of communicating with his fellows.

And getting out, he suspected, was going to take some doing.

Although, as this passage makes clear, the purpose of the excursion is not strictly medical, the story still features many of the same tropes that were seen in The World Inside and which would recur in many later narratives, including leucocyte attacks, travel in the blood stream and excursions through the heart and lungs.

Eventually Dark makes himself heard by his host (a low ranked member of the human space navy who had sneaked out to a bar) and then irritates the trachea so he is coughed out and later spontaneously re-expands in his boss’s office. Satisfyingly, the aliens prove to be misunderstood and desperate since their world is being destroyed, and they have been misled into agression by the first human they encountered.

Not really involving medicine at all and not entering into the human, but also exploring many of the same tropes is The Invisible Army by Ross Rocklynne (novella, published in Thrilling Wonder Stories, Winter 1944) This is set in the immediate aftermath of World War II, where a dastardly ex-Nazi scientist miniaturises first a girl reporter, Ileen Caput, and then her scientist father and inventor fiancé. The German scientist Maurer proves to have smuggled a fully-equipped Nazi army, a million soldiers strong, into America on a set of microscope slides, and it is into their care that the captives are placed. Rocklynne liked to explore physics problems in his stories, and naturally provided an attempted rationalisation:

Maurer had discovered an electro-magnetic vibration which compressed atomic electrons closer to their nuclei without damaging the dynamic stability of the whole. Such vibrations could shrink any object to one forty-three-thousandth of its original size,

Special suits had been designed for the men selected, suits which would compress the rarified atmosphere to breathability.

The soldiers are kept battle-ready by fighting germs and bacteria. Ultimately the solution for the three captives proves to involve miniaturising themselves still further, to atomic scales where the protagonists are pummelled by Brownian Motion, before returning to full size and handing the slides over to the authorities.

Returning both to the human body and to the alien invasion theme of The Bridge to Earth is Shock Troop, a short story by Daniel F Galouye (Galaxy, June 1957), which was also faithfully adapted into an episode of radio drama anthology X-Minus-One by George Lefferts in November of the same year. This is told from the perspective of a military commander whose Valvarezian troop is balancing highly technical tasks with fighting. The technical side involves tapping into the audio systems, vision, other senses, oxygen supply and ultimately conscious control of a much larger host creature (macro-organism), with the intent of opening its bodily cavities for civilian colonisation. This presents substantial risks of lethal shock to the psycho-electricians involved in tapping major nerves. The military side involves fights with leucocytes and battling against the fluids of the enormous body. It only gradually becomes clear that the host creature in question (described as “intelligent, but only to a degree”) is a human… who proves to be a captive prisoner.

The narrative is notable for its description of the humid heat of the human body, as well as the relentless pulse of its circulation and the impact that has on the crews:

Commander Lasson was haggard and dispirited as he slumped beside the control console. It was difficult to dislodge from his thoughts the hordes of shapeless white horrors that lurked just beyond the thinly calcified walls. He sighed in resignation, realizing that he might forget them if it weren’t for that infernal thrump- thump, thrump- thump that was a constant reminder of the nearness and profusion of the treacherous capillaries.

Lasson loosened the soggy and wilted collar of his uniform and swiped his face with a limp hand. Damned insufferable heat! Filthy, rotten, putrid air!

While the intention of the troop is to bring internal temperature, pulse, air supply, convulsion and voluntary movement under their own control before colonisation, the planned invasion - hosting a million Valvarezians in the cavities of each human - is ultimately prevented by the pure chance of the shock troop colonising a condemned prisoner.

Fantastic Voyages

Released in 1966, the blockbuster Hollywood movie Fantastic Voyage (dir: Fleischer) reached far beyond the conventional science fiction audience and had a lasting influence on narratives of miniaturised exploration of the human body. At least in part, this was likely due to the casting of popular actress Raquel Welch as one of the explorers, but also to the ground-breaking special effects (which won an Academy Award) and striking visualisations (the film won a second Academy Award for Best Art Direction) shown on screen.

The film described an American-Soviet Cold War based on the secret possession by both sides of a miniaturisation technology which can reduce objects for a strictly limited time. A defecting Russian scientist claims to have a solution for the time limit, which might open the way for miniaturised armies and other unpredictable outcomes, but is seriously injured before he is able to tell his new nation the secret. A neurosurgeon, his female assistant, a miniaturisation scientist and a submarine pilot are miniaturised in a submarine, the Proteus, together with the intelligence agent who extracted the scientist, Benes, from the USSR in the first place. Injected into Benes’ body (rendered hypothermic to give them more time and reduce activity), the Proteus and its crew must make their way to his brain, destroy a devastating blood clot and be extracted before their strict one hour time limit expires and they kill the patient through expansion.

The film follows the subsequent adventure, which includes diversions to the heart (which must be briefly stopped to prevent their destruction by pressure waves) and lungs (which are tapped to replenish the air supply), encounters with antibodies and the dangers of the inner ear, along with multiple sabotage attempts, before they escape the body. Despite its impressive visuals, and a reasonably accurate depiction of the body and its contents, the film is relatively sparse on technical or physical explanation. It includes a number of inconsistencies - including a radioactive particle that is not miniaturised along with the ship and so provides its nuclear power, no real explanation for what a submarine is doing on the base, and the fact that the destroyed Proteus and the dead saboteur are left in the body (in the grip of a leucocyte) as the others escape and expand.

Some of these scientific flaws were addressed by Isaac Asimov in his 1966 novelisation of the film. Ironically, since the film was delayed during the production process, the novelisation appeared well before the film itself was released, leading to confusion over which came first. However both Asimov and the forward to his book by Otto Klement were careful to point out that the novel Fantastic Voyage was written by Asimov, based on a screenplay by Harry Kleiner for a film directed by Richard Fleischer, adapted by David Duncan, based on a story by Otto Klement and Jay Lewis Bixby - with the long chain of creatives (as well as the special effects) perhaps contributing to the film’s troubled production and delays.

Asimov’s novelisation introduced a number of elements to address the physics of the premise, including discussions of surface tension (a substantial problem at these scales), turbulence and brownian motion (the random motion of all particles at temperatures above absolute zero, which, as we’ve seen before, can be significant at cellular scales), as well as the effect of miniaturisation on light and vision. He invoked the Heisenberg uncertainty principle to tie the timescale for reversion to the extent of miniaturisation. He also explains that its miniaturisation uses a hyperdimension to miniaturise the air, atoms and the space in between, but that this makes the ship fragile, and adds complications. When trying to refuel from the lungs, for instance, the crew must miniaturise the air molecules with equipment fitted aboard the Proteus for deep-ocean sample collection (thus giving at least a superficial reason why it might be on base). Asimov ensures that the white blood cell engulfing the Proteus’ wreckage is lured out of the body during the escape of the survivors through a tear duct. Interestingly, he also gives Cora Peterson (Raquel Welch’s character) a scientific identity and motivation of her own, discussing her frustration that her appearance distracts others from her academic qualifications and competence - this differs substantially from the film where she remains silent for the first ten minutes or so after her appearance.

Fantastic Voyage was sufficiently successful to launch a spin-off animated series, also called Fantastic Voyage, which aired in 1968-9 and featured a new crew (comprising a military hero, a geeky male scientific genius and a female biologist, as well as a mystical psychic guru) and new multi-element vehicle, the Voyager, combatting crime and scientific mysteries alike in twelve-hour time-limited missions. These typically did not involve travel within the human body, but instead more general miniature adventures “to combat the unseen, unsuspected enemies of freedom!” akin to those in other narratives [4].

Setting aside the animated series, Asimov returned to the premise more than twenty years later with his longer novel Fantastic Voyage II: Destination Brain, published in 1987, and apparently written as a potential treatment for a never-realised feature film sequel. In an authors’ note, he explicitly noted his frustrations with the 1966 film he was asked to novelise, and his intention to deal with the premise in the way he felt it should have been handled this time, rather than yielding to outside pressure.

Like the original film, Asimov’s sequel novel was firmly contextualised in the Cold War, although in this case set well into the twenty-first century, during a period of semi-raprochement, where hostilities are officially ended, but Soviet identity, national pride and the desire for precedence remains strong. In this respect, the novel feels rather aged now, failing to anticipate the collapse of the USSR at the end of the twentieth century, which was imminent even when it was written. 

The story is told from the viewpoint of a failing American neurophysicist, Albert Morrison, who is kidnapped from a scientific conference and spirited away to a secret Soviet scientific base, the Grotto, which is working on miniaturisation. Their lead scientist, Shapirov, has been injured and the soviet team believe that Morrison’s unorthodox theories regarding interpretation of brain patterns will enable them to tap into Shapirov’s comatose mind and reveal the secret that will make miniaturisation practicable. Against Morrison’s strenuous objections, he is forced to accompany the mission to tap the scientist’s neurons, gradually overcoming his own cowardice and reluctance to become involved with the mission as he tries to prove his own theories.

The miniaturisation in this novel differs from that in the film or earlier novelisation by explicitly invoking a change in Planck’s constant as its mechanism. This constant represents a fundamental property in quantum physics, defining the length scale on which quantum effects become important, the time scale on which they occur, and the energy scale required for quantum manipulation. The insight which the dying Shapirov is believed to have would couple the Planck constant of quantum physics with the constant speed of light in relativistic theory, and thus free the technique from the need for a vast energy input and from the ever-present random risk of sudden de-miniaturisation with accompanying explosive energy release [5].

Miniaturisation is presented as a metastable state that can be disrupted by energy loss and quantum fluctuations (including energy transfer through Brownian motion) and whose disruption becomes more likely for smaller fields (e.g. micronauts lost in the bloodstream as opposed to inside the vessel) or as time passes. Unlike many of the other examples discussed here, the vessel in this case is also able to adjust the extent of its own miniaturisation, shifting from microbe-sized in the bloodstream to molecular scales as it enters individual neurons.

The narrative features many now-familiar incidents, including discussion of the various organic structures, encounters with leucocytes and individual scuba-diving in bodily fluids. Unlike many of the other stories, though, this vessel does not make a side trip to the heart and lungs, and broadly remains within the environs of the brain. It also makes it back to the hypodermic needle intended to retrieve it, rather than needing to short cut through a bodily orifice. Despite this, the mission is ultimately a failure, but the novel ends with hopeful possibilities for the future of Morrison’s work, and the miniaturisation project, which make a pleasant contrast to the cynicism and the angsty, stress-ridden interpersonal relationships and personalities which shape the majority of the narrative.

More recently still, the Fantastic Voyage premise was reimagined yet again. Fantastic Voyage III: Microcosm by Kevin J Anderson (novel, 2001) updated the setting to the post-USSR world and to modern technologies. As if miniaturisation wasn’t enough excitement, the plot involves a miniaturised crew comprising a pilot, medic, security agent and a self-proclaimed UFO-expert exploring the body of a crash-landed alien rather than human. Amidst still-chilly US-Russian relations and a possible diplomatic incident, their new vessel, called the Mote, has only around five hours to explore, finding analogues to human nerves, blood vessels and organs… and also finding nanotechnology apparently infesting the alien body. Anderson was careful to keep the mechanism behind the miniaturisation vague, but was respectful of his influences, mentioning a previous 1960s miniaturisation project as well as referencing a range of science fiction sources including Star Wars and Star Trek. As we’re told:

“Here, deep in the mountain, the metal desk reminded him of the scientific glories of the 1950s and 60s when people had believed that technology would solve the world’s problems. Hunter wanted to recapture that sense of infinite possibilities.”

Later Voyages

Since the 1966 release of Fantastic Voyage, its imagery and premise have recurred repeatedly throughout science fiction and beyond.

Perhaps one of the most obviously influenced movies is 1987’s InnerSpace (film; dir: Dante). This comedic interpretation sees a volunteer in an experimental submarine miniaturised and transferred to a syringe, preparatory to exploring the inside of a rabbit. An attack during the experiment, and subsequent events, result in the pod (containing volunteer pilot Tuck Pendleton) injected into an unsuspecting supermarket worker. Tapping the optic nerve, Pendleton realises he is in a human and moves to the inner ear to communicate with his surprised and terrified host. There follows a chaotic chase, involving spies and Pendleton’s girlfriend, given particular urgency by the need to reenlarge Pendleton before his limited oxygen supply is exhausted.

Here the miniaturisation is not really explored in detail, and the goal is research rather than medical treatment, but many of the same tropes and visualisations are invoked, and a memorable scene involves the pod finding its way unawares (after transfer to another host) to a human uterus. By manipulating particular nerves, Pendleton is able to control the movement of his host, Jack, in a manner reminiscent of the theme in Shock Troop. The film also shows Pendleton using nervous control to manipulate Jack’s facial muscles into imitating the appearance of a specific individual - which seems less than likely given the importance of underlying bone structure in defining appearance.

A far grimmer treatment can be found in The Men Inside (novel, 1973; first published in the UK in 1976) by Barry N. Malzberg. This describes a year 2022 with extreme economic inequality, where young men are recruited from deprived slum areas to be trained as “Messengers” - individuals who are minimised to the scales of eightieths of an inch and sent into the human body to excise cancerous growths under a strict time-limit, before exiting through the anus, and then nursing the patient back to health. The patients of the private clinic in question must be extremely wealthy and thus are almost inevitably elderly and unpleasant.

The narrative is written in a conversational style, inviting the reader to explore the psychology of one of the messengers and his increasing mental disintegration, driven by childhood abuse, the quasi-religeous training he undertakes, the inequality he confronts, the hideous organic realities of entering the human body, and, above all, the sexual dysfunction that results from the “Hulm projector” minimisation process. Through a series of flashbacks, hallucinations and increasingly extreme and sexual dreams, the narrative concludes with the messenger using his miniaturisation technology to take the same life he had saved.

At this scale the protagonist is less troubled by blood cells and bacteria than other examples, and the technology is largely ignored in favour of the psychological drama, providing an example of how this ability - particularly if it remains expensive or restricted by social policy - could be misused and abused.

By contrast, far less negative treatments can be found in not one but several stories in the television series Doctor Who. “The Invisible Enemy” was a 1977 serial featuring Tom Baker’s Fourth Doctor and his companion Leela. Best remembered for introducing the robotic dog K-9 (and for a giant glittery plastic prawn costume), the story involves a research base located on Saturn’s moon Titan. The base is infected with an intelligent virus known as the Nucleus. When the Doctor also becomes infected, he is taken to a medical base in the asteroid belt, where he and Leela are cloned. The short-lived clones (with lifespans of ten or eleven minutes) are miniaturised by TARDIS dimensional stabiliser technology and, animated by a consciousness that mirrors their originals, enter the Doctor’s body to hunt out the virus. The Nucleus escapes through the Doctor’s tear duct, and is then magnified into the macroscopic world, where it rampages through the base before being destroyed by Titan’s atmosphere.

The story is not particularly well-regarded. Setting aside the mind-boggling idea of exploring inside one’s own body, the scientific elements push the limits of suspension of disbelief, blithely ignoring the difficulties of consciousness-transfer, cloning and miniaturisation, as well as the ethical dilemma of what happens to the clones after their use, the ethics of killing the sentient virus, the manifestation of a ‘mind-brain interface’, not to mention the creation of the artificially-sentient K-9. It is nonetheless an interesting tale. The story is let down by its eccentric acting and direction, laughable costumes and budget-limited special effects, which fall far short of those made familiar by Fantastic Voyage, but it still maintains a sense of tension and contains striking imagery of the Doctor’s internal workings, including cavernous structures, bursts of neural energy and a thumping pulse, as well as an attack by white blood cells.

Moving into the modern era, the series introduced the human-appearing robot Teselecta in several episodes featuring Matt Smith’s Eleventh Doctor and his companions Amy and Rory, starting with "Let’s Kill Hitler" (TV episode, 2011). While the entire humanoid was a constructed vehicle, rather than an actual person, it was occupied by a crew of hundreds of miniaturised humans who controlled its movements and reactions. The Teselecta routinely took the form of a human being, with its eyes being portals, its controls mirroring those of a human body, and its corridors patrolled by ‘antibodies’ - semi-autonomous robots who hunted down unauthorised intruders. This imae of a mechanised human controlled by tiny people appeared in earlier stories including films such as Men in Black (1997), and Meet Dave (2008). Aside from being a robot itself, the Teselecta’s internal organic architecture echoes earlier science fiction stories such as Shock Troop, as well as other fantasies involving sentient beings inhabiting regions of the human body (as, for example, in Pixar’s 2015 film Inside Out) or imparting sentience to microscopic biological elements like cells (as in the 2001 film Osmosis Jones).

Returning to organic life, Doctor Who again reprised the idea of miniaturised internal medicine, adjusting the premise to explore an alien body and exoskeleton in the 2014 episode “Into the Dalek”. In the midst of a Dalek-Human war, Peter Capaldi’s Twelfth Doctor and his companion Clara are miniaturised by a “moleculon nanoscaler”:

“It miniaturises living matter. What’s the medical application though? Do you use it to shrink the surgeons so they can climb inside the patient?”

“Exactly.”

“Fantastic idea for a movie. Terrible idea for a proctologist.”

The machine is used to miniaturise the Doctor and Clara in order to assist a group of human soldiers with healing their best hope for peace - a single, badly-damaged Dalek who appears to be sympathetic to the human cause. Since a Dalek is a cyborg, a mutant organic creature intimately merged with a cybernetic shell, the environment they enter mixes the organic with construction, with mechanical antibodies reacting to accidentally-inflicted injury, and protein soup. The Dalek, nicknamed Rusty, communicates lyrically with the Doctor and the others inside him about life prevailing. However, saving Rusty’s life from an internal radiation leak proves to ‘cure’ the Dalek of the malfunction which made it ‘good’. Again little explanation is given for the “nanoscaling” process, but that is incidental to the plot. Exploring the hugely-magnified interior of the Dalek, is instead a metaphor for exploring the psychology of the Dalek and of the Doctor himself, who was still early in his regeneration and uncertain of his intrinsic goodness.

Meanwhile, the legacy of Fantastic Voyage’s popularity can also be seen in endless respectful imitations and parodies in the context of other fictional series, particularly in animated television series (where the necessary special effects are relatively straightforward) with examples in series ranging from Captain Planet and the Planeteers to The Simpsons, Family Man, Transformers and Muppet Babies [6].

 A notable example can be found in the science fiction comedy cartoon series Futurama. In the 2001 episode “Parasites Lost”, the protagonist Fry ingests a contaminated sandwich. His colleagues create microscopic identical robot copies of themselves, which can be controlled by immersive virtual reality headgear and gloves. Through these, they explore Fry’s digestive system, uncovering and seeking to destroy a huge civilisation of sentient worms. Ironically, the worms had actually been improving Fry’s physical condition and mental acuity, making him more sensitive and attractive, and it is only the desire to know whether his love-interest Leela is attracted to him or his parasites that leads Fry to accept the cure.

The story here is largely played for comedic effect, and indeed jokes about how impossible miniaturisation of actual people (as in Fantastic Voyage) would be. But - like many Futurama episodes - it has elements of pathos and genuine dilemma, including questioning to what extent an individual is simply the sum of their physical elements, and can be modified by changes to them. It’s also interesting to see a relatively early example of miniaturised robot avatars taking the place of the genuine explorers (albeit controlled by human, and other, minds).

Internal Medicine

As I’ve discussed before, the process of miniaturising humans is almost certainly impossible for multiple physical reasons. Energy requirements, quantum limits, conservation of mass, and the inability to see or breathe all come into play. Science fictional explanations including compressing atoms, gravity nullifiers, manipulating hyperdimensions or modifying Planck’s constant or the atomic fine structure constant do little to explain how such processes could be achieved. Despite this, the continuing interest in such stories is clear. As always, it’s interesting to look at some of the themes emerging from these narratives and how the emphasis in those themes has changed over time.

Particularly for the earlier stories discussed above, there is a clear interest in the interior of the human body as an environment and series of processes which, in the 1930s, 40s and even 50s, were still relatively little understood. The properties of red and white blood cells, nerves, muscles, germs and bacteria began to be uncovered with the creation of the first microscopes, which also fuelled a fascination with the idea of an unseen microscopic world, but the detail gradually improved as both analysis equipment and knowledge of atomic chemistry developed towards the end of the nineteenth century. Microbiology of human bodies was far less likely to be taught at school level in the early twentieth century than in later decades (where, for instance, the basics of blood, circulation, energy exchange in cells etc formed part of the national school curriculum for all children in the UK from the late 1980s).

Thus in the early stories, readers were likely learning about such processes as phagocytosis (the ingestion of germs by white blood cells) for the first time. This is evidenced in the fairly frequent asides and technical explanations injected into examples such as 1936’s The World Inside. In this respect, it’s a relatively rare example of science fiction deployed as education in the medical sciences. Unlike in many of the physical sciences, misunderstanding of medical truths, or their confusion with science-fictional extrapolations, is frequently a matter of life and death. As a result, the blending of fiction with clear scientific description is seldom a good idea. Even as late as 1966, when Fantastic Voyage was released, though, many viewers would not have been taught a clear picture of many processes within the human body - and certainly would not have been able to clearly visualise them. For many, the cavernous blood vessels and striking imagery of that film helped inform their visual, as well as intellectual, understanding of the human body as an organism.

Another theme running through this fiction is the sense of the human body not just as an organism but as a machine, with reactions and movements that can be brought under conscious control. The idea that applying the right currents to nerves can lead to physical control can be traced back through the vast literature of body horror to early examples such as Mary Shelley’s Frankenstein, and ultimately to experiments such as the stimulation of motion in frogs legs by nineteenth century scientists. All of these fuelled philosophical and moral questions as well as scientific ones - in a culture that was taught to regard humanity as the pinnacle of divine creation, the idea of reducing its physicality to the level of machinery was, and remains, shocking. Indeed, questions about the morality of research in this area continue, with clearly beneficial medical uses such as neural control of replacement limbs balanced against less clearly motivated animal studies such as remote-controlled cyborg pigeons.

This ability to tap into vision and hearing, as well as control limbs, and hence to reduce human organs to useful equipment is a recurring theme in stories of minitiarised medicine - as is the wider question of how this relates to the sense of identity and humanity that arises from simple organic machines. This is often implicit in the text rather than discussed directly, but is touched on in particular by Asimov’s Destination Brain, in which the thoughts of the patient are of paramount interest. The disjoint between using a human body as an automaton and understanding its motivations and reactions to its environment is also brought into sharp relief in Galouye’s Shock Troop.

However, perhaps the most interesting theme in the narratives discussed here, and the one which has seen the most impact and progress in reality, is the realisation that surgery that can address problems on the microscopic scale, at the site of an injury or problem, would be far superior to any form of surgery through open incisions. While even the most enthusiastic medical researcher has probably always recognised the miniaturisation of human beings to undertake this as lying at the extreme end of the science fiction range, the idea of miniaturising the tools used, and for controlling their operations inside a human being has long had a growing and continuing traction.

The minimally invasive surgery undertaken through key hole incisions, with flexible tools fed through the circulatory system to a selected site, has strong resonances with the fiction of vessels undertaking the same journey, but is now routine in a way that it was not in the 1960s. It is commonly used in operations ranging from gynaecology to gasterology. The use of medical imaging equipment to track and position such tools echoes that used to track the Proteus and other vessels in fiction.

Also increasingly common is the use of microsurgical robots - systems that track the movements of surgeons on a human scale and translate them into microscopic manipulation of equipment inserted inside the human body. While this falls a long way short of the miniaturised robotic avatars imagined in examples such as Futurama, it is perhaps a stepping stone towards such a technique. Another step is the advent of injectable technology which acts autonomously rather than under remote control. Such robots for internal medicine have long been an objective of both science fiction and medical research, and now look likely to come to fruition in the relatively near term. Indeed several of the technologists and medical researchers involved have spoken of being inspired by the film Fantastic Voyage and similar narratives, and press releases from both academic institutions and media outlets use the term fantastic voyage as a shorthand for describing such nanomedicine devices. 

At the extreme end of this path is perhaps the nanotechnology (atomic-scale robots) which feature so prominently in Anderson’s Microcosm, and which form a widespread complementary theme in science fiction [too extensive to deal with here, and in need of a separate blog entry]. Where those nanobots are used for medical treatment (up to and including cosmetic and longevity maintenance) they fall into a science fictional tradition which can be traced back through the narratives here to the early pulps and earlier.

The science fictional vision of fantastic human voyages inside the human body is likely never to be realised - the problems involved in miniaturisation are just too profound. However the images of the interior of blood vessels and organs which wowed science fiction readers and the cinema-goers of the twentieth century can now be routinely captured by microscopic cameras and have helped directly inspire the development of technologies which save countless lives today. Where they take us into the future remains to be seen.