50 PIGMENTARY GROWTH AFTER ABLATION OF 



losl by hypophysectomy has been supplied these albinous larvae 

 exhibiting a normal growth rate, since it will be noted that this 

 anterior-lobe substance was fed daily and formed their entire 

 food supply aside from a small component of lettuce. This 

 seems the more probable if the conception usually held in regard 

 to 'hormonal' substances be correct, namely, that minute 

 amounts are effective. But that this substance must be sup- 

 plied continuously is clearly shown by three groups of albinos: 

 1) a group receiving anterior-lobe substance once each week, 

 liver being fed on the other days; 2) a group receiving anterior 

 lobe until an average length of 36 mm. (on July 18th) had been 

 attained, a liver diet then being instituted; 3) a group (the 

 converse of group 2) reared on a liver diet until they had attained 

 an average length of 33 mm. (on September 7th), the liver diet 

 then being replaced by anterior lobe. 



The growth curve of the first group, those receiving anterior 

 lobe once a week, although considerably modified, resembles 

 that of the liver- rather than that of the hypophysis-fed group 

 (fig. 2). Though the incidence of the early retardation is slightly 

 deferred, nevertheless the 'critical point' appears in the usual 

 position, though in a less pronounced manner. After a brief 

 period of depression, the curve rises in a regular manner until 

 the level of the normal is attained. Their curve thus resembles 

 that of the liver-fed albinos, and the ultimate size attained by 

 these specimens is intermediate between that of the anterior- 

 lobe- and that of liver-fed specimens. 



The second group, those receiving anterior lobe until July 18th, 

 grew at a normal rate up to and for approximately two and 

 one-half weeks past the time when the liver regime was insti- 

 tuted (fig. 2). A definite growth retardation then appeared, 

 the specimens eventually attaining the size of their unoperated 

 companions, but failing by some 10 mm. to reach the size of 

 their operated mates supplied throughout their growing period 

 with glandular hypophysis. 



The specimens of the third group, those supplied with liver 

 nn til they had attained a size of 33 mm., had suffered the usual 

 early growth retardation and the pronounced midlarval slowing 



