544 Proceedings Columbia Biochemical Association [July 



contains, would seem to indicate that there may be a possible rela- 

 tionship between Rhizopus and some of those diseases, such as 

 Pellagra, the "corn-stalk disease," and the "horse disease" of the 

 Middle West, the causes of which are at present unknown, but 

 which have been supposed to be due to infected food. We are at 

 present carrying out a series of investigations on the chemical 

 nature of the Rhizopiis toxin, as well as its possible relation to such 

 diseases, and we hope to be able to make a more detailed report in 

 the near future. 



87. Studies on melanin : V. A comparison of certain nitro- 

 gen ratlos in black and in white wool from the same animal. 

 Ross AiKEN GoRTNER. (Biochcmical Laboratory of the Station 

 for Experimental Evolution, The Carnegie Institution of Wash- 

 ington.) Black and white wool from a pied lamb were analyzed 

 by Van Slyke's method, with the following average percentage 

 results (corr. for solubilities of the bases) : 



White wool Black wool 



Ammonia nitrogen 9.32 9.46 



Humin nitrogen 1.20 4.74 



Arginine nitrogen 1746 16.81 



Lysine nitrogen 3.90 3.97 



Cystine nitrogen 2.70 3.09 



Histidine nitrogen 7.00 7.04 



Amino nitrogen (filtrate) 54-54 52.04 



Mon-amino nitrogen (filtrate) 2.76 2.13 



Total 98.88 99.27 



The nitrogen content of the black wool was 15. 11 per cent. and of 

 the white wool, 16.27 per cent. 



By subtracting the humin nitrogen for the white wool from the 

 corresponding fraction for the black wool we have 3.54 per cent. 

 of the nitrogen as due to the melanin present in the black wool, I 

 have already shown^ that the pigment which remains when the 

 melanin from wool is treated with boiling conc. hydrochloric acid, 

 contains 8.48 per cent. of nitrogen. Using these data I have calcu- 

 lated the percent of nitrogen which would be present in the black 

 wool providing that the nitrogen due to the melanin, as given by 

 the acid hydrolysis, were not present, at the same time correcting 



ö Gortner : Bull. soc. chim. de France, 1912, xi, p. 498. 



