Chapter VII. 



The Question as to the Isolation of the 

 Sexual Hormones. 



A. EXTRACTS OF THE WHOLE SEX GLAND. 



In Chapter HL we considered the experiments which have 

 been made upon the injection of the sexual glands and their 

 extracts to show how greatly our knowledge of internal 

 secretion has been influenced thereby. We must never forget 

 that it was through the experiments of Brown-Sequard^ with 

 subcutaneous injection of testicular extracts that our know- 

 ledge not only of the internal secretion of the sexual glands, 

 but of internal secretion in general began. It is well known 

 that the experiments of Brown-Sequard have been much 

 disputed; we have already discussed this question at some 

 length in the third chapter. But notwithstanding all the 

 objections which have been made, the fact remains that here, 

 as so often in the history of science, new scientific principles 

 and new knowledge were established on disputed, or even really 

 erroneous, data. 



After Brown-Sequard, repeated attempts were made to 

 obtain from the gonads the chemical substances corresponding 

 to the sexual hormones. The determination of the characters 

 of these substances by an elementary chemical analysis, or the 

 establishment of their chemical constitution was not attempted 

 until later. Several investigators, however, tried to isolate 

 the hypothetical hormones from the gonad. The great thera- 

 peutical successes with preparations of the thyroid, and the 

 new exact knowledge of adrenaline gave a powerful incentive 

 to similar attempts to isolate the internal secretions of the 

 gonads. But so far the results of all recorded experiments 

 with injecting these extracts have been disappointing. It is 

 true that many effects have been described — effects on the 

 nervous system, on the circulation, on the metabolism, and 



1 On the role played by Brown-Sequard in the estabhshment of endo- 

 crinology see G/ey'5 book (1914), especially p. 22. 



319 X 



