INTERNAL SECRETIONS in 



becomes much thicker in pregnancy, while the medulla becomes 

 thinner (Gottschau). The removal of the gonads also influences 

 the other internally secretory organs, and notably the anterior 

 lobe of the pituitary, which enlarges under this condition. 



Conversely, lesions or abnormalities in the organs of internal 

 secretion are known to affect the gonads. Thus hyperpituitarism, 

 due to over-activity of the anterior lobe, is often associated with 

 premature sexuality or excessive desire. On the other hand, a 

 lesion in the pituitary may be followed by atrophy of the semini- 

 ferous tubules, as in cases of dystrophia adiposogenitalis, where 

 the individual affected becomes abnormally fat as well as sterile 

 (Cramer and Mottram). Removal (or partial removal) of the 

 anterior lobe is followed by hypoplasia of the generative organs, 

 or if the operation is done before puberty by persistent infantilism. 

 After removal of the thyroid glands, generative activity is said 

 to cease, but this result may be due to the general metabolic 

 disturbance. 



The relation between the thymus and the gonads is more 

 problematical, but as already said, castration favours persistence 

 of the thymus which otherwise atrophies about puberty. 



The view that there is a foetal organ of internal secretion 

 in the gonad, and that this is the main cause of sex-determination, 

 is referred to in the next chapter. 



The Gonads and Rejuvenation 



The idea of a connection between testicular or ovarian in- 

 fluence and rejuvenation was put forward by Brown-Sequard 

 about 1889, and formed part of a general theory concerning the 

 metabolic effects of the gonads. The theory was based chiefly 

 upon the supposed beneficial results of injecting extracts of 

 testis and ovary, obtained from .animals, into aged men, and 

 although tentatively accepted by some, was soon discredited, as 

 it became evident that the rejuvenating eft'ects claimed were 

 apparent rather than real. What is essentially the same idea 

 has been recently brought into prominence again by Steinach 

 and others, and more especially with reference to the inter- 

 stitial or " puberty " gland. The grafting of a human testis 

 from one individual to another seems to have been first done by 

 the American surgeon Lespinisse, and Stanley and Kelker, 



