68 DARWINISM STATED BY DARWIN HIMSELF. 



ter, who had this strange habit ; and certainly imitation 

 was in this instance out of the question. 



INHEEITED DISEASES. 



Animals and Large classes of diseases uusally appear at 

 Plants, vol. certain ages, such as St. Vitus's dance in youth, 

 11, page . consiim ption in early mid-life, gout later, and 

 apoplexy still later ; and these are naturally inherited at 

 the same period. But, even in diseases of this class, in- 

 stances have been recorded, as with St. Vitus's dance, 

 showing that an unusually early or late tendency to the dis- 

 ease is inheritable. In most cases the appearance of any 

 inherited disease is largely determined by certain critical 

 periods in each person's life, as well as by unfavorable 

 conditions. There are many other diseases, which are 

 not attached to any particular period, but which certainly 

 tend to appear in the child at about the same age at which 

 the parent was first attacked. An array of high authori- 

 ties, ancient and modern, could be given in support of 

 this proposition. The illustrious Hunter believed in it ; 

 and Piorry cautions the physician to look closely to the 

 child at the period when any grave inheritable disease 

 attacked the parent. Dr. Prosper Lucas, after collecting 

 facts from every source, asserts that affections of all kinds, 

 though not related to any particular period of life, tend 

 to reappear in the offspring at whatever period of life they 

 first appeared in the progenitor. 



Esquirol gives several striking instances of 



insanity coming on at the same age as that of 



a grandfather, father, and son, who all committed suicide 



near their fiftieth year. Many other cases could be given, 



as of a whole family who became insane at the age of 



