This principle of biologic degeneration, long recognised, was most lucidly enforced by Dohrn[24], whose views were later extended by Ray Lankester. The parallelism of animal degeneracy with that of man, so clearly evident even in the parasitic nature of defectives, was, as Meynert[25] showed, due to the fact that the fore-brain is an inhibitory apparatus against the lower and more instinctive natural impulses. The higher its development the greater is the tendency to subordinate the particular to the general. Even in insects a high social growth occurs, as in the bee and ant communities. The same is the case in the development of man; in the infant, a being entirely wrapped in its instincts of self-preservation, the "primary ego" is predominant and the child is an egotistic parasite. As development goes on this standpoint is passed, conscience assumes its priority, the fore-brain acts as a check on the purely vegetative functions and the "secondary ego" takes precedence over the primary one; this is the general order of society, designated as civilisation or social order. If this inhibition become weakened or disordered, predominance of the natural instincts or impulses occurs, and when it is totally lost the individual is in the position of a criminal who opposes the ethical order of society--a parasite, and one of the worst kind who not only lives upon his host but destroys him in doing so. Hence degenerate tendencies are reversions in type indicating the original source of the inhibition. The tree of Moreau[26] illustrates clearly the essential principles of these inter-relations of defect, further elucidated by the observations of Sander[27] on the connection of deformed central nervous systems with mental and moral disorder. _NERVOUS HEREDITY._ { Science { Music. Exceptional Intelligence { Arts { Painting. { Letters { { Paretic dementia. { { Paralyses. { Brain { Tumours. Lesions of the Nerve Centres { { Brain Softening. { { Congestion. { { { Softening of Spinal { Spinal Cord { Cord. { { Myelitis. { Epilepsy. { Chorea. Neuroses { Stammering. { Convulsive Fits. { Hysteria. { Utopians. Intellectual States { Eccentrics. { Mixed Conditions.