brain-testicles homology, which functioned not as a direct but an inverse relationship. The origins of the homology can be explained partly as the legacy of classical medical theorists, the majority of whom believed that semen originated in the brain,37 and that excessive seminal loss would therefore debilitate the brain. Tissot’s anti-masturbatory tract cites this model of inverse relationship as a historic remnant of classical thought: “Hippocrates thought it was extracted from all the body, and particularly the head…. Galen is of this opinion … [that] When a person loses his seed … he loses at the same time the vital spirit: so that it is not astonishing that too frequent coition should enervate, as the body is thereby deprived of the purest of its humours” (48–49). Venette, likewise, would acknowledge the literalism of the ancients’ notion of a balanced fluid economy, reporting that “The brain … has been diminished to that degree in some lascivious men, according to Galen, that it has not been bigger than one’s fist” (162–63). The force of the older model is evident in other sexologies, as well, which sometimes appear to accept the classical theory without modification, as does Marten’s Gonosologium Novum in accounting for one of the causes of impotence:
Figure 1 Leeuwenhoek’s drawings of spermatozoa, “Observations Di. Anthonii Leewenhoeck, de prognatis è Semine genitali Animalculis,” Philosophical Transactions, No. 142, 1678. Courtesy of The Wellcome Library, London.
So will a man’s being wounded behind the Ears … whereby certain branches of the Jugular Veins and Arteries that are there have been cut; so that after those Vessels have been cicatriz’d, there follows an interception of the Seminal Matter downwards, and also of the community, which ought of necessity to be between the Brain and the Testicles; so that when the Conduits or Passages are stopp’d, the Stones or Testicles cannot any more receive either Matter or lively Spirits from the Brain in so great quantity, as it was wont. (41)
As these passages suggest, the older thesis survived in the sexologies, which offered readers a simplistic literal version of the brain-sperm connection: interrupt the downward flow from brain to testicles and sperm would be deficient; discharge too much sperm and suffer a brain-drain (usually figured as lassitude, headache, blurred vision, dizziness, stupidity; sometimes as madness or death, as in the anti-masturbation diatribes). But the brain-testes homology was also intensified by newer studies in reproductive physiology such as De Graaf’s which, having explained the confection of semen as a refinement of blood within the testes (see his Tractatus 29–32) rather than of nervous fluid or blood within the brain, were now more keenly interested in the physiological dynamics by which blood and animal spirits were shared by brain and testicles. One result was that the literalism of the classical linkage of brain and sperm was replaced by a homology in which brain and testicles were seen to have a correspondence of structure and function—that is, the brain produced animal spirits from the blood just as the testicles produced semen from the blood. As Jean Baptiste Verduc put it in A Treatise of the Parts of a Human Body (1704), “nothing can give us a clearer Idea of the vast Activity of the Seed, than the Similitude, which is betwixt those Parts which prepare the Seed, and the Brain. These two parts in short, have in a manner the same Structure; they both consist of several small Pipes which suck in the most spiritous parts from the Mass of the Blood; and so we may say that the Testicles are in a manner a second Brain, since they do filtrate as the Brain doth, a Liquor which is almost as penetrating, and as spiritous as the Animal Spirits.”38
Of course, the shift from literal to homologous connection did not happen in a vacuum, and depended on parallel developments in neuroanatomy and new theories about cerebral and neurological function, particularly as they were set forth by Thomas Willis, arguably the most significant neurophysiologist of the early modern period.39 In writing of the nerves which affected the testicles, and wanting to correct the erroneous belief that semen was derived from nervous fluid in the brain, Willis offered an account of the interrelationship of seed, blood, animal spirits, brain, and testes which provided the dominant conceptualization of such matters through much of the eighteenth century. Excessive discharge of semen, he reasoned, produces a general debility of brain and nerves because the replenishment of seed requires an immediate flow of blood and animal spirits to the genital area, thus temporarily robbing the brain of its own requirements.40 But while Willis’s and De Graaf’s physiological models helped to banish older connections in favor of the more complex similitude later described by Verduc, what they retained from classical assumptions was the notion that brain and testicles were still linked by a complex fluid economy which functioned as an inverse hydraulic relationship. As major physiological entities in the hierarchy of bodily organs, the brain and testicles shared the same system of fluids, competing for animal spirits or vital matter in the blood; according to nearly every commentator in the seventeenth and eighteenth centuries, maximum health and stability were achieved for each organ and for the body as a whole when a happy physiological balance of fluid-making and fluid-use could be maintained. Within what has been called “the sublime order of the spermatic economy,”41 this meant neither the excessive discharge nor prolonged retention of semen. Reflecting the state of knowledge at mid-century, Robert James’s A Medicinal Dictionary (1745) would present the orthodox view that “Retention of the Semen induces a Torpor and languid State of the Body, and often lays a Foundation for terrible nervous Disorders…. Venery ought to be only moderately used, lest too great an Evacuation of the Semen should prove prejudicial to Health…. Nor should Persons indulge themselves in Venery after strong Application of Mind” (3: s.v. “VENUS”). A balanced fluid economy assured health, and this entailed occasional rather than frequent sexual intercourse; masturbatory emission was unnecessarily wasteful and potentially harmful. Excessive venery might not shrink one’s brain to the size of a fist, as Galen had warned, but it would surely interfere with a man’s ability to think.
But the inverse relationship of brain and testicles via sperm was not merely a mechanical matter. What was most significant about the updated use of classical literalism was the newer conceptualization of the relationship of male body and male mind encouraged by the homology itself. And in this regard, the impact of Willis’s neurophysiological theories are particularly important. Because concepts of mind and soul were now commonly localized as brain and nervous system, the newer male brain-male genitalia correspondences—whether direct or inverse—were not simply issues of animal health, but also raised important questions about how masculine consciousness might be informed by the organs of generation. The seventeenth and eighteenth centuries had inherited from classical medical models an identification of maleness with the reproductive system, but the meaning of that system had changed as a result of improved physiological experimentation, the advent of the microscope in medicine, and new embryological and neurological speculation. The older symbolism, as we have seen, was about hierarchy and analogy in which seed, yard, and testes were one of many markers linking the man to issues of legitimacy or power within the frameworks of law, citizenship, paternity, or reproductive potency. The medicalized version of the moderns absorbed some of these older constructions, but now viewed genitalia as an important effect on the brain/mind; reproductive biology, in other words, was generating a model of an essentialized maleness whose consciousness and experiential history might be understood as linked to the condition and activities of the sexual parts.
But it is in the non-medical discourses that we find the larger cultural ramifications of how the genitals-mind correspondences were absorbed and then played out through a variety of verbal codes, many of which informed the self-mythologizing narratives of male literary communities. From the most simplistic mechanical versions of the equation to the sophisticated adaptations of Laurence Sterne, the historical record reflects an interest in this newly sexualized male brain whose sensibility and deepest thinking could be understood as inescapably linked to the privy parts. As we will see, the interrelated head and groin were often conceived in subtle symbolic terms, as in Diderot’s epistolary observation that “Il y a un peu de testicle au fond de nos sentiments les plus sublimes et de notre tendresse la plus epurée” [“There is a bit of testicle at the bottom of our most sublime feelings and our purest tenderness”].42 This is a complex notion,
