THE LA WS OF HEREDITY. 73 



reversion to the original family type; and where the 

 character is of the pathological order, as in insanity, 

 gout, idiocy, and the like, it may be taken that the 

 character, or tendency thereto, is present in every 

 generation, but in some remains latent all through life, 

 either because it has been too far mitigated by the 

 infusion of the untainted blood of the other parent, or 

 because it has not received some necessary fillip to act 

 as a starting-point or exciting cause. 



Of this latency of characters we have many examples. 

 The most commonly cited is gout, but there is a much 

 more remarkable instance to be found in families show- 

 ing the haemorrhagic diathesis commonly known as 

 " bleeders." Here the peculiar morbid condition is 

 purely hereditary, and although it has been rarely, 

 if ever, seen in the female, it is regularly transmitted 

 through the females to the males of the next gene- 

 ration. It may even be transmitted through two or 

 three generations of females, to reappear in the males 

 so soon as that sex appears in the family. Dr. Wick- 

 ham Legg * and Dr. Finlayson ( have studied this sub- 

 ject, and have published family trees illustrating this 

 strange fact. In explanation of this " sexual atavism," 

 if it may be called so, of the haemorrhagic diathesis, I 

 would submit that the morbid condition present in 

 these cases was almost from the first necessarily fatal 

 to the females, it being impossible for a woman of this 

 diathesis to pass safely through parturition, or even 



* St. Bartholomew's Hospital Reports, 1881. 

 t Glasgow Medical Journal, July 1882. 



