74 



Scientific Proceedings (97). 



(protein). With diarrhea sulfur does not appear to be quite as 

 well absorbed as the nitrogen. Although normally very little 

 chloride is eliminated by the intestine, the amount found in the 

 stools may be considerably increased in diarrhea. About one 

 third of the total phosphorus output of the intestine and kidney 

 is found in the stools. The percentage output in the feces of both 

 calcium and magnesium is high, due, as we believe, to the lacto- 

 vegetarian diet, which resulted in a poor absorption of compounds 

 of these elements. As might be anticipated from our knowledge 

 of potassium salts, a very appreciable amount of this element is 

 eliminated in the feces, and diarrhea considerably accentuates 

 this elimination. In general it may be said regarding the intes- 

 tinal diarrhea, that, although it very definitely reduces the ab- 

 sorption of nitrogen, sulfur, chlorine and potassium, it appears 

 to be almost without influence on the phosphorus, calcium and 

 magnesium. 



43 (1418) 



The pigment changes in frog larvae deprived of the epithelial 



hypophysis. 



By P. E. Smith (by invitation). 



[From the Anatomical Laboratory, University of California.] 



It has been known for a considerable time that in the fishes, 

 amphibia and reptilia remarkable changes in color pattern or 

 external appearance occur. It is also generally known that these 

 effects are due to the reciprocal interplay of alterations in at least 

 two great systems of pigment-bearing cells, the bearers of dark 

 pigment (melanophores) and the bearers of various other pig- 

 ments, many of them metallic lustered (xantholeucophores). To 

 the latter class of pigments the trout owes its silvery appearance. 



Somewhat over two years ago the author, followed shortly by 

 B. M. Allen, showed that peculiar silvery frog larva? were invari- 

 ably produced when the epithelial portion of the hypophysis was 

 removed in early embryonic stages. For the sake of brevity these 

 individuals were designated "albinos" and are always in con- 

 spicuous contrast to the darker, normal specimens. As might 



