218 BIOLOGY OF DEATH 



lost througli old age, and a general loss of senile bodily 

 characteristics and a resumption of the conditions of 

 full adult vigor in those respects, together with a consid- 

 erable increase in the total duration of life. 



Space is lacking to go into the many details of 

 Steinach's work, much of which is indeed chiefly of inter- 

 est only to the technical biologist, and from a wholly 

 different standpoint than the present one. I should, 

 however, like to present one example from his experi- 

 ments. As control, a rat was taken, in the last degree 

 senile. He was 26 months old when the experiment be- 

 gan. He was obviously emaciated, had lost much of his 

 hair, particularly on the back and hind quarters. He 

 was weak, inactive and drowsy, as indicated by the fact 

 that his eyes were closed, and were, one infers from 

 Steinach, kept so much of the time. 



A litter brother of this animal had the efferent ducts 

 of the testes ligated. This animal, we are told, was, at 

 the time of the operation, in so much worse condition of 

 senility than his brother, above described, that it was not 

 thought worth while even to photograph him. His con- 

 dition was considered hopeless. To the surprise of the 

 operator, however, he came back, slowly but surely after 

 the operation, and after three and a half months pre- 

 sented a perfect picture of lusty young rathood. He 

 was in full vigor of every sort, including sexual. He 

 outlived his brother by 8 months, and himself lived 10 

 months after the operation, at which time he was, accord- 

 ing to Steinach, practically moribund. This represents a 

 presumptive lengthening of his expected span of life by 

 roughly a quarter to a third. It is to be remembered, 

 however, that Slonaker's rats to which nothing was done 

 lived to an average age of 40 months. 



