Preface. 



It has been known from very early times that castration in 

 both man and animals, besides suppressing the sexual 

 instincts, causes marked differences in the conformation of the 

 body and the secondary characters of sex, and, moreover, that 

 these results are most definite if the operation be performed 

 before maturity has been attained. Numerous references to 

 this subject occur in the works of Aristotle, who comments on 

 the extensive modifications brought about in the general 

 configuration as a consequence of the mutilation of a compara- 

 tively minute organ. The manner in which this influence is 

 exerted, however, has only been ascertained comparatively 

 recently, and although great progress has been made in the last 

 few years there are still wide gaps in our knowledge. 



According to Berman, the author of a work on The Glands 

 Regulating Personality, the first to put forward the idea that 

 the gonads produce their effect through substances discharged 

 into the^blood was Bordeu, court physician to Louis XV., in the 

 eighteenth century. It would appear, however, that Berthold 

 in 1849 was the first physiologist to base the conception on 

 experimental investigation. Little account was taken at the 

 time of Berthold's work, and it was not until considerably 

 later that the idea of an endocrine organ which elaborated a 

 secretion transmitted through the medium of the blood was 

 revived by Claude Bernard to describe the glycogenic and 

 sugar-producing activities of the liver. The conception of 

 internal secretion received a great stimulus from Brown- 

 Sequard's experiments with the injection of testicular extracts 

 in 1889, and although the vahdity of this particular work soon 

 became discredited, it served a useful purpose in directing 

 attention to the study of the endocrine organs and the possi- 

 bilities of appl57ing it practically in medicine. Brown- 

 Sequard's views, which he extended so as to refer to all the 

 elements of the body, contributed largely to the adoption of 

 organotherapy, the methods of which have been applied 

 to all the organs of internal secretion as well as to others of 

 problematic or unknown function. It was not until much more 



