28 PIGMENTARY GROWTH AFTER ABLATION OF 



rated by an hypophysial deficiency leads to an upset in the pig- 

 mentary system, will it not be possible with the proper endo- 

 crine diets to abort or ameliorate this derangement? The possi- 

 bility appears the more probable since the general growth effects 

 inherent in the loss of the buccal hypophysis can be prevented 

 by the administration of the beef glandular lobe, as will be shown 

 later. 



Of the endocrine substances which have been fed, glandular 

 lobe and neural lobe (with the pars intermedia) of the hypophysis, 

 adrenal cortex, adrenal medulla, and liver, one only the neural, 

 or posterior lobe has caused a formation of epidermal melanin 

 approaching the normal, while none have reduced the xantholeu- 

 cophores to a normal state of contraction. 



It was early seen that those specimens receiving the posterior 

 lobe of the pituitary exhibited a darker appearance than the 

 albinous larvae fed upon the other fresh glands (figs. 46 to 51). 

 Although expressed feebly at first, this depth of color became 

 more pronounced as the feeding and growth progressed. So 

 pronounced did it become after five months of this diet that 

 there would have been some uncertainty in identifying these 

 as hypophysectomized specimens save for the fact that legs 

 did not develop. An examination of the living animal with the 

 binocular reveals that although the xantholeucophores are 

 typical of albinos, i.e., are fully expanded, there has been a great 

 replacement of the epidermal melanin. This replacement was 

 readily confirmed by a study of whole mounts of the epidermis 

 which reveal that both components of the epidermal melanin 

 have been increased (compare figs. 21 to 23 with figs. 14, 20). 

 The free pigment is not, as in the typical albino, distributed in 

 diffuse aggregations, but is found in considerable amounts in 

 all of the superficial epidermal cells. The epidermal melano- 

 phores also show a depth of color never attained in the typical 

 albino, as is most clearly shown if the processes of the broadly 

 expanded melanophores (a condition readily obtained by the 

 death of the animal) of the posterior-lobe-fed albino be com- 

 pared with those of the albinos on any other diet. 



