As J. G. Kiernan shows,[12] this doctrine, early in the history of the race, obtained dominance through the evolution of arts, sciences, and religions from fetichism. Phenomena manifested by fetich priests (of the Shaman type) so closely resembled epileptic insanity in its frenzies and visions that the two states were long regarded as identical, whence the term “morbus sacer.” The supernatural influences which, in current belief, underlay epilepsy were, at the outset, malign or benign as they were offended or placated. They became benign, and the insane were under protection of a deity, as in Mussulman countries. Later still the demon-possession theory gained dominance, and at length the demon sank into disease. Throughout all this evolution the belief in an inherent affinity between insanity and genius persisted.
Aristotle, in whose day the disease notion was becoming dominant, asserts that, under the influence of head congestion, persons sometimes become prophets, sybils, and poets. Thus Mark, the Syracusan, was a pretty fair poet during a maniacal attack, but could not compose when sane. Men illustrious in poetry, arts, and statesmanship are often insane, like Ajax, or misanthropic like Bellerophon. Even at a recent period similar dispositions are evident in Plato, Socrates, Empedocles, and many others, above all, the poets.
According to Plato, “Delirium is by no means evil, but when it comes by gift of the gods, a very great benefit. In delirium the sibyls of Delphi and Dodona were of great service to Greece, but when in cold blood were of little or none. Frequently, when the gods afflicted men with epidemics, a sacred delirium inspired some men with a remedy for these. The Muses excite some souls to delirium to glorify heroes with poetry, or to instruct future generations.”
Precedent to the works of Morel and Moreau appeared their source and inspiration, Prosper Lucas’s Natural Heredity.[13] Here the biologic current of thought encountered the sociologic current; although the waves clashed, the two currents merged into and modified each other. The biologist demonstrated that degenerate types often “threw back” in their structures, and this very “throwing back” made them the fittest to survive. The sociologist found that the only test of acquired or inherited degeneracy in man was disaccord with environment. The co-existent moral and physical defects resultant on heredity found by Erasmus Darwin, Rush, Parkman, Grohmann, and others tended to show that all types of defectives might be a product of heredity.
These stimulating researches into the sources of crime led to a controversy which reached its height two decades ere the treatise of Morel. To this controversy three suggestive works owed their origin: a psychological treatise by Dr. Lauvergne[14] on felons, a romance with a purpose by Eugène Sue,[15] and a suggestively practical brochure by a rather corrupt police official, Vidocq.[16] Seemingly conflicting as were these productions, all strikingly illustrated the influence of heredity and environment in the production of defectives. To these productions were soon added those of Moreau (de Tours),[17] Attemyer, Eliza Farnham,[18] the American Sampson,[19] Dally, Lélut, Camper, and the older Voisin.
Morel[20] laid the foundation of what is widely known as the Lombroso School by a brochure wherein he proposed to entitle morbid anthropology, “that part of the science of man the aim of which is to study phenomena due to morbid influences and to malign heredity.”
To the factor of atavism, inconsistently ignored by Morel, the early embryologic studies of Von Baer and the biologic studies resultant on the transmutation of species lent special emphasis. Three possibilities of life await, as Wilson[21] remarks, each living being: either it remains primitive and unchanged, or it progresses toward a higher type, or it backslides and retrogresses. The factors underlying the stable state force the animal to remain as it is; those underlying the progressive tendency make it more elaborate, while the factors of degeneration, on the other hand, tend to simplify its structure. It requires no special thought to perceive that progress is a great fact of nature. The development of every animal and plant shows the possibilities of nature in this direction. But the bearings of physiological backsliding are not so clearly seen.
That certain animals degenerate or retrogress in their development is susceptible of ready and familiar illustration. No better illustration is needed than is derived from the domain of parasitic existence. When an animal or plant attaches itself partly or wholly to another living being, and becomes more or less dependent upon the latter for support and nourishment, it exhibits, as a rule, retrogression and degeneration. The parasitic “guest” dependent on its “host” for lodging alone, or it may be for both board and lodging, is in a fair way to become degraded in structure, and, as a rule, exhibits marked degradation where the association has persisted sufficiently long. Parasitism and servile dependence act very much in structural lower life as analogous instances of mental dependence on others act on man.
The destruction of characteristic individuality and the extinction of personality are natural results of that form of association wherein one form becomes absolutely dependent on another for all the conditions of life. A life of mere attachment exhibits similar results, and organs of movement disappear by the law of disuse. A digestive system is a superfluity to an animal which, like the tapeworm, obtains its food ready made in the very kitchen, so to speak, of its host. Hence the lack of digestive apparatus follows the finding of a free commissariat by the parasite. Organs of sense are not necessary for an attached and rooted animal; these latter, therefore, go by the board and the nervous system itself becomes modified and altered. Degradation wholesale and complete is the penalty the parasite has to pay for its free board and lodging; and in this fashion Nature may be said to revenge the host for the pains and troubles wherewith, like Job of old, he may be tormented.
The most emphatic biologic degeneration is that discovered by Kowalevsky[22] in the sea squirt, which, in its larval state, is a vertebrate, and when adult is an ascidian, seemingly far below the cuttlefish and the worms. This strikingly illustrates that, as Ray Lankester[23] has said, degeneration is a gradual change of structure by which the organism becomes adapted to less varied and less complex conditions of life; a reverse of evolution which proceeds from the indefinite and homogeneous to the definite and heterogeneous with a loss of explosive force due to the acquirement of inhibitions or checks.