191 1 ] A, J. ROSANOFF AND FLORENCE I. ORR 229 



lay informants related to the neuropathic conditions. At the 

 same time we have counted as normal all cases of mental or 

 nervous disturbance resulting from arteriosclerotic disease with 

 strokes, paralyses, aphasias, etc. 



§ 4. Dissimilar Heredity. Degrees of Recessiveness. 



Heretofore we have dealt with the neuropathic constitution as 

 a unit, comparing it with the normal condition. The great variety 

 of neuropathic manifestations and the facts of dissimilar heredity 

 show, however, that the neuropathic constitution in reality con- 

 sists of a series of entities which are distinct, at least from the 

 standpoint of clinical definition, though at the same time evidently 

 in some manner related to each other. 



The phenomenon of dissimilar heredity has, indeed, in the 

 opinion of some cast a doubt upon the validity of conclusions 

 which are in part based upon the assumption of the existence of 

 an essential relationship between the most diverse clinical neuro- 

 pathic manifestations. It must be admitted that the burden of 

 proof rests upon those who assume that imbecility, epilepsy, de- 

 teriorating psychoses, periodic psychoses, paranoic conditions, 

 involutional psychoses, the slighter psychopathic states, and certain 

 eccentricities are all etiologically related. It is for them to explain 

 why the neuropathic constitution leads in some cases to death 

 from convulsions in early childhood, and in others to but a transi- 

 tory depression at the involutional period, the subject being at 

 least approximately normal during the greater part of his life. 

 It is for them to explain why in some cases there is profound 

 congenital mental defect, in others a dementing process coming 

 on in early adult life, in still others recurrent but non-dementing 

 insanity, and in others again a mere predisposition to mental dis- 

 turbance which for many years remains latent and is brought to 

 light only through the operation of some external cause. 



Some parts of our material seem to throw some light upon the 

 nature of the relationship which exists between various neuro- 

 pathic manifestations. Thus the pedigree charts of at least four 

 families point to the existence of different degrees of recessive- 

 ness. In other words, certain neuropathic conditions, though 

 clearly recessive as compared with the normal condition, are at 

 the same time dominant over other neuropathic conditions which 



