THE PITUITARY BODY 



glandularis. Of equal or greater importance is the genetic 

 constitution of the individual. One example may be quoted. 

 Robb (1928) determined the weight of the pituitary body in 

 dwarf (Polish) and giant (Flemish) rabbits. There was no 

 correlation between the weight of the pituitary and the 

 growth-rate or the adult body-weight. In fact, the pituitary 

 bodies of adult rabbits of both breeds weighed about the 

 same, but the relative weight of the pituitary of the giant 

 rabbits was about one-half that of the dwarf race.' A heredi- 

 tary defect of the pars glandularis may be responsible for a 

 marked inhibition of growth and final body-size as in the 

 mice of Smith and MacDowell (1930-31). The inhibition of 

 growth and development of Eidmann's tadpoles {Rana escu- 

 lenta) may have been of both genetic and endocrine origin 

 (Eidmann, 1921). 



So far as the glands of internal secretion are concerned, the 

 pituitary is unquestionably the most important and the most 

 essential regulator of growth. Disturbances of growth may 

 also be clearly present after the removal of the thyroid or the 

 gonads. Also, there can be little doubt but that the growth- 

 promoting principle of the pituitary is elaborated in the pars 

 glandularis. The weight of the anatomical evidence is in fav- 

 or of the view that the hormone is secreted by the oxyphil 

 cells (see chap. i). 



To determine the effects of the pituitary body or its parts 

 on growth, the following methods of administration have 

 been employed; feeding (including possibly cutaneous ab- 

 sorption in larval amphibia), transplantation, implantation, 

 and the injection of extracts. 



THE EFFECTS OF FEEDING THE PITUITARY BODY 

 OR ITS PARTS 



Feeding experiments, employing the pituitary or the pars 

 glandularis as all or part of the food, have been performed in 



' The weight of the pituitary body, of course, is not necessarily related to the 

 secretory capacity of the gland. 



[82] 



