NORMAL AND PATHOLOGICAL GROWTH 159 



tions in the alimentary tract are kept 

 on a normal level, and the rate of se- 

 cretion of the hormones of the thyroid 

 and of the suprarenal itself are regu- 

 lated and controlled, because the epi- 

 nephrine specifically stimulates the 

 nerve endings of the thoracic sympa- 

 thetics wherever they may be found. 

 It raises blood pressure, favors sugar 

 metabolism, and Boothby 12 has shown 

 that it has a specific dynamic action in 

 raising the rate of metabolism. It does 

 not take extreme scientific training to 

 appreciate that such physiological re- 

 actions are at the very foundation of 

 activity, nutrition, and growth. The 

 point is that the suprarenal hormone 

 operates so subtly that we cannot al- 

 ways point with certainty to the exact 

 part it plays in the process. We again 

 emphasize that the study of growth by mass measurements or 

 by any other method must take into account the factors which 

 influence the details of the functional process, hence the growth 

 processes. 



V. The Hormones of the Reproductive Gonads 



The interstitial tissues of the reproductive gonads, the corpus 

 luteum and follicles of the ovary, and the placental membranes 

 all yield growth-stimulating substances. The best known of 

 these are from the female ovary. It has long been known that 

 domestic animals and the human do not develop the character- 

 istic body type of either the male or female of the species until 

 the sex gonads are mature, and that certain parts of the repro- 

 ductive system atrophy on removing the gonads. It was only in 

 1900 that Knauer first proved that these atrophies failed in 



Figure 8b. Masculine form of a 

 woman due to a tumor which 

 increased the secretion of the 

 cortex of the suprarenal gland. 

 After surgical removal of the 

 tumor the beard was lost and the 

 form slowly returned to the 

 feminine type. From Gould and 

 Pyle's Anomalies and Curiosities 

 of Medicine. By permission of 

 W. B. Saunders Company, Phila- 

 delphia. 



