THE PARS BUCCAL1S OP THE HYPOPHYSIS 107 



13. The evidence thus indicates that the neural lobe and 

 pituitary floor are dependent upon the epithelial hypophysis 

 for their complete development, and further that an atypically 

 placed epithelial hypophysis has the power to cause an hyper- 

 trophy of the adjacent neural tissue. 



14. Since 'partial' albinos may be secured in which the pig- 

 mentary upset or albinism is nearly as profound as in those 

 larvae which have suffered a complete epithelial ablation, and 

 since in these instances none of the endocrine glands are gravely 

 impaired in development save the hypophysis, and since the 

 feeding of posterior lobe (plus pars intermedia), alone, of the 

 major internal secretory glands effects a partial replacement 

 of the epidermal melanin in the albino, and further since no 

 extract save that of the pars intermedia induces a normal physi- 

 ological state in the pigmentary system of this animal, it seems 

 justifiable to refer the endocrine fault responsible for the pig- 

 mentary disturbance to the posterior lobe or the posterior- 

 intermediate lobe secretory mechanism and to free the other 

 glands from responsibility. 



15. The frog tadpole suffering from complete or incomplete 

 hypophysial deficiency exhibits even after a long period of 

 inanition or after a prolonged metamorphosis a fat-organ un- 

 diminished in size, in contrast to the small size of this organ in 

 similarly treated thyroidless tadpoles or in normal tadpoles 

 near the end of metamorphosis. The persistence of the fat- 

 organ in these tadpoles appears to simulate the adiposity ex- 

 hibited by the mammal suffering from hypophysial deficiency. 



16. The frog tadpole which has suffered the early loss of 

 its epithelial hypophysis exhibits a retardation in growth when 

 supplied with a continuous diet of liver, posterior lobe, adrenal 

 cortex, or adrenal medulla. This growth retardation is feebly 

 expressed at first, but becomes very pronounced at about the 

 midlarval period. 



17. A continuous diet of the fresh anterior lobe of the beef 

 replaces the growth-'maintaining' substance lost by buccal hy- 

 pophysectomy and so effects a nearly normal rate of growth 

 in the albinous frog tadpole. Since these animals do not meta- 



