Flesh in the Age of Reason (9 page)

The last of the humours, black bile (melancholy), entered disease theory late, but in the Hippocratic
On the Nature of Man
, it assumed the status of an essential, if mainly deleterious, humour. Visible in vomit and excreta, it was thought of as responsible for the dark hue of dried blood. Indeed, the idea of four humours may have been suggested by observation of clotted blood: the darkest part corresponded to black bile, the serum above the clot was yellow bile, the light matter at the top was phlegm. Black bile completed a coherent,
symmetrical grid of four humours in binary oppositions, and the four humours – blood, yellow bile, black bile and phlegm – then proved wonderfully versatile as an explanatory system. They could be correlated to the four primary qualities (hot, dry, cold and wet), to the four seasons, to the four ages of man (infancy, youth, adulthood and old age), to the four elements (fire, air, earth and water), and to the four temperaments (sanguine, bilious, melancholic and phlegmatic). They thus afforded a neat schema with unlimited explanatory scope. On the assumption, for example, that blood predominated in spring and among the young, precautions against excess could be taken, either by eliminating blood-rich foods, like red meat, or by blood-letting (phlebotomy) to purge excess. The scheme – which finds broad parallels in traditional Chinese and Indian medicine – could be made to fit with observations and afforded rationales for disease explanation and treatment within a causal framework.

The Hippocratic medicine developed in Antiquity grounded itself on nature, on physical reality – not in the spiteful whims of the gods, broken taboos, or the spells of malicious sorcerers, all of which were now dismissed as superstitious. It is no accident that the Greek term for nature (
physis
) gives us our words physics and physician. But to say that it was concerned with the physical – with poor diet or the consistency of a sick person’s stools – does not mean that it drove a wedge between the material body and the mind. Far from it: Greek medicine was holistic through and through; it presumed the unity of body and behaviour; the physical and the psychological were two sides of the same coin. And its cast of thinking ensured profound and enduring holistic psycho-somatic and somato-psychic strands in the Western tradition.

To explain what activated the flesh, ‘animal spirits’ were posited, superfine fluids which shuttled between the mind and the vitals, conveying messages and motion. (‘Animal’ here does not mean pertaining to the beasts but rather relating to the soul or
anima
.) And, following Aristotle, the revered ‘father of biology’ earlier discussed, classical medicine held that various ‘souls’ respectively governed specific bodily functions: the ‘vegetable soul’ directed nourishment
and growth (what we would today call autonomic processes and metabolic regulation); the ‘animal soul’ governed sense, feeling and motion (similar, in our terms, to the sensory/motor system); and the ‘intellectual soul’ regulated the mental powers, that is, what medieval and Renaissance theorists of human nature were to group as the inner senses of reason, will, memory, imagination and judgement. These ‘souls’ were corporeal.

In classical medicine, the materiality of the flesh, far from excluding the idea of ‘spirit’, accommodated and even required it. Responsible for purposive functions and movement, animal spirits were central to Galenic medicine – and thence to subsequent European philosophizings about life for the next millennium and a half. After all, for the soul to act on the flesh, was there not an evident need for bridging media, partaking of the properties of both? Spirits formed precisely those intermediaries. Even when the rational soul was not consciously in charge, spirit represented the vivifying element present, for instance, in the digestive juices or in semen, imparting to them their vigour. Such spirits drew their potency, many thought, from an aerial substance in the atmosphere, the
pneuma
, or divine spirit, breathed into the lungs.

In all such formulations, ‘spirit’ conveys subtly nuanced shades of meaning: not all ‘spirit’ was what we would today call ‘spiritual’. One meaning pertains to the purely immaterial, as, with the coming of Christianity, the Holy Ghost or Holy Spirit – a spirit which presupposes a difference in kind (the ‘spiritual’) from things gross, concrete or fleshly. But ‘spirit’ chiefly conveyed the idea of an exceedingly fine medium, the most ethereal possible, far more delicate than the ponderous substance which ‘matter’ might routinely suggest. The value of the term ‘spirit’ in traditional biomedical discourse lay in this very flexibility.

Galenic medicine identified an innate spirit (
spiritus insitus
) which pervaded all parts of the body, approximately the equivalent of ‘life’ in the most general sense. It found expression in the body’s ‘innate heat’ and ‘primitive moisture’: without these, there could be no animation. These were what differentiated the living from the inani
mate. In addition to this general innate spirit, specific spirits were elaborated – the natural, the vital and the animal. These were superfine in character and relatively localized, being produced in and by specific organs, namely, the liver, the heart and the brain respectively. Each played a special physiological role.

Dominant Galenism also assimilated the Aristotelian doctrine that objects consisted of form and matter. Matter was a potential which could be actualized by form – for instance, wood could be ‘in-formed’ into a branch or a table. Matter was thus indeterminate, inchoate, rather low-grade stuff, awaiting the form which articulated and enhanced it; but it was also the ‘principle of individuation’ – what made things particular or unique. Tables were universal in their (Aristotelian) form or (Platonic) Idea – every table had legs and a top, and was for putting things on; but it was the particular type and piece of timber which made this or that table distinctive – which gave it its ‘quiddity’, its dimensions (or quantity), grain and shade. Qualities or virtues, in other words, were those powers possessed by forms which made them capable of bringing about change in matter. The form of man was the soul, and the soul was the form of the body. In Aristotelian and Galenic thinking, dynamic activity depended on the form; the soul was thus the mover and end (final cause) of all the actions of living bodies (not just humans).

A human being was thus represented in traditional biomedicine as a complex, differentiated but integrated whole (the Platonic or Christian immortal soul, as we have seen, brought additional complications). The humours formed one facet, and their disposition was reflected in the ‘complexion’ (or outward appearance) and the ‘temperament’ – or, as we might say, personality. Humours, complexion and temperament constituted an interactive system, equipped with feedback loops.

Within this framework, illness was standardly read not as a random assault from outside, but as a significant life-event, integral to the sufferer’s whole being, spiritual, moral and physical, to his or her humoral balance, and to his or her life-course, past, present and future. This view partly stemmed from ingrained beliefs about what
caused illness. The explanations offered by doctors regarded good health as a measure of the orderly workings of the individual constitution, and sickness as a sign of its imbalance. To maintain good health, one needed to ensure proper diet, exercise, evacuations, adequate sleep and the like. It was important to reside in a healthy environment, to regulate one’s passions, and be moderate and temperate in habits.

Sickness set in when bodily balance was disturbed. If the system grew too hot and dry, this came out in fever; if too cool and wet, it developed a cold. If too little blood were produced, the body lacked nourishment and languished. If excessive blood were generated, for example by drinking too much red wine, one’s blood would boil or rush to the head; ‘hot-blooded’ people were liable to apoplexy or stroke. Thus sickness was largely seen as personal, internal, and brought on by faulty lifestyle. Such ‘distempers’ (being out of temper) could be treated by restoring the lost equilibrium; hence ‘cooling’ herbal medicines, blood-letting (phlebotomy) or even cold baths would be good for fevers, while plenty of rich food and red meat would cure ‘thin blood’. The enduring popularity, likewise, of purging and blood-letting hinged on the old conviction that sickness followed plethora (excess) or the build-up of ‘peccant’ (evil) humours in the system, requiring periodic discharge. Better still, attention to all aspects of ‘regimen’ or lifestyle would prevent or mitigate disease (literally ‘dis-ease’) in the first place.

This classical framework for understanding the body and the swings of health and sickness, developed in the Hippocratic writings and systematized by Galen, retained its hold throughout the Middle Ages into early modern times. It was rich, inclusive and flexible; it codified common sense and was open to minor alterations. It was first comprehensively challenged by the ‘new philosophers’ of the seventeenth century. Their mechanical models of nature implied that, precisely like all other inanimate objects, living bodies were machine-like, governed by the universal laws of matter (corpuscles) in motion. ‘Mechanical philosophers’ thus looked upon the body as
a piece of machinery, and, proclaiming that science was a matter of action not words, encouraged hands-on experimental investigation.

The new science launched a war on empty words, on reification. All that old Aristotelian talk (potential and actualization, substance and accidents, qualities and quiddities) and the thinking behind it was now dismissed as futile and fruitless verbiage, mere hot air. As Francis Bacon avowed in his dismissal of Aristotelian final causes (teleology), scholasticism was like a barren virgin which brought forth nothing. Claiming, by contrast, to possess an understanding of matter which was rooted in reality (
res non verba
: things not words), the ‘new philosophers’ returned to the alternative tradition of atomism, advanced in Antiquity by Epicurus, Democritus and Lucretius but largely sidelined. Ridiculing all the old scholastic blather, they substituted a model of nature composed of matter in motion, and held that matter itself was made up of corpuscles or particles operating in a plenum (according to Descartes, who denied the vacuum) or in void space (as for Newton), whose motions could be given mathematical expression. ‘Instead of using only comparative and superlative Words and intellectual Arguments,’ explained William Petty, a founder-fellow of the Royal Society, ‘I have taken the course… to express myself in Terms of
Number
,
Weight
, or
Measure
.’ Behind what John Locke called ‘secondary qualities’ such as colour, smell and so on, which were essentially subjective, lay rock-solid ‘primary qualities’ – mass, velocity, acceleration.

Through the innovations of Descartes, Gassendi, Boyle, Hooke, Huygens, Newton and many others, the mechanical philosophy transformed physics and astronomy in the seventeenth century; inevitably it also prompted new research programmes in anatomy, physiology and medicine. Investigators were spurred to view living creatures mechanistically, as ingenious contraptions made up of skilfully articulated components (bones, joints, cartilage, muscles, vessels), functioning as levers, pulleys, cogs, pipes and wheels, in line with the laws of mechanics, kinetics, hydrostatics, and so forth. The body became a
machina carnis
, a machine of the flesh.
Faced with the question, ‘What makes bodies tick?’, the obvious answer given by the mechanical philosophers was that they went by clockwork.

In these developments, William Harvey proved a crucial but transitional and ambiguous figure. The revolutionary anti-Galenic conclusion of his
Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus
(An Anatomical Disquisition Concerning the Motion of the Heart and the Blood in Animals: 1628) that the blood continually circulated around the body, driven by a heart which functioned as a pump, became grist to the mill of new philosophers from Descartes onwards. But Harvey himself thought along Aristotelian teleological principles, and it was left to a younger generation to hail his discoveries as evidence in favour of the mechanical philosophy.

One such was Marcello Malpighi. Drawing on the marvellous new invention the microscope, this Professor of Medicine at Pisa conducted a remarkable series of studies into the structure of the liver, skin, lungs, spleen, glands and brain, many of which were published in early numbers of the
Philosophical Transactions
of the Royal Society, chartered by Charles II in 1662. Also in Italy, Giovanni Borelli, among other ‘iatrophysicists’ (doctors convinced that physics provided the key to the body’s operations), studied muscle action, gland secretions, respiration, heart action and neural response. His main contribution was a treatise,
De Motu Animalium
(On Animal Motion: 1680), which set out remarkable observations on birds in flight, fish swimming, muscular contraction, the mechanics of breathing and a host of similar subjects, and attempted, more boldly than any before him, to comprehend bodily functions in terms of mechanics. Investigating what made the body machine work, he postulated the presence of a ‘contractile element’ in the muscles; their operation was triggered by processes similar to chemical fermentation. Respiration for its part was a purely mechanical process which drove air, via the lungs, into the bloodstream. Familiar with the air-pump experiments conducted by Otto von Giercke in Germany and Robert Boyle in England, in which small creatures expired in ‘rarefied’ air (that is, a vacuum), Borelli maintained that ‘aerated
blood’ included elements vital to life. Physics and chemistry together, aided by experimentation and the apparatus, both technological and conceptual, provided by the mechanical philosophy, thus promised to lay bare the secrets of life, buried in the flesh and long veiled by scholastic jargon.

Borelli’s younger contemporary, Giorgio Baglivi, Professor of Anatomy at the Papal School in Rome, represented the culmination of this ‘iatrophysical’ programme. His
Praxis medica
(1699) affirmed that ‘a human body… is truly nothing else but a complex of chymico-mechanical motions, depending upon such principles as are purely mathematical’. Baglivi, however, was only too well aware of the predicament staring champions of scientific medicine in the face: frustratingly, their theories and studies did not seem to yield more effective cures.