EVIDENCES ASSOCIATING PINEAL GLAND FUNCTION 

 WITH ALTERATIONS IN PIGMENTATION 



CAREY PRATT iMcCORD and FLOYD P. ALLEN 



Detroit, Michigan 



SEVEN FIGURES 



INTRODUCTION 



In the spring of 1915 we undertook to establish the influence 

 of pineal gland substances upon growth and difTerentiation proc- 

 esses in tadpoles. The tadpoles employed were hatched in 

 the laboratory and immediately placed upon a diet of pineal 

 gland. On the tenth day of larval life it was readily observable 

 that in the pineal fed groups the coloration was uniformly lighter 

 than in the control, muscle-fed groups. This alteration was 

 at first attributed to some unknown difference in environmental 

 conditions — light, background, etc., as the color of these or- 

 ganisms was known to vary considerably in response to such 

 stimuli. These changes when first noticed were trivial in de- 

 gree, but as development progressed the alterations in pigmen- 

 tation became correspondingly greater. Thirty minutes after 

 feeding pineal tissue, the tadpoles which prior to the feeding 

 had been uniforml}^ dark, became so translucent that all the 

 larger viscera were plainlj' visible through the dorsal body wall 

 (figs. 1 and 2). This translucency appeared with such regu- 

 larity and so punctually after pineal feedings and was so mark- 

 edly absent in the control groups that the phenomenon was 

 made the subject of special study. Out from this work have 

 come many acceptable e\'idences of a pineal gland influence 

 upon pigmentation, upon the phases of colloidal state, and upon 

 the vegetative nervous system. 



The following report is the record of the unfolding of this 

 further work. 



207 



