58 



THE SEX-COMPLEX 



Effects of 



tracts. 



tremors, excessive perspiration and the rest are 

 Produced. 



Feeding with small doses of thyroid extracts has 

 long been known to stimulate growth in the larval 

 stages of amphibian development. For instance, tad- 

 poles may be brought to maturity in eighteen days 

 after being hatched, the usual period that elapses in 

 normal circumstances being about twelve weeks. 



There is little doubt, then, that normal growth may 

 be stimulated and accelerated, and that under-growth 

 especially when due to thyroid insufficiency may be 

 successfully treated. 



As some of our information, such as the augmenta- 

 tive effect of thyroid feeding on the suprarenal medullary 

 secretion, has no direct bearing on our subject it will be 

 sufficient here to recall the atrophy produced in the 

 uterus by thyroidectomy (p. 54), and to mention that 

 therapeutical indications based on this knowledge will 

 be set forth in the second part of this work. 



