FEEDING COLOR AN AID IN STUDYING PHYSIOLOGICAL 



DEVELOPMENT 1 



BY C. A. ROGERS 



The coloring of animal tissues with Sudan III was known as early as 

 1896 by an Italian Scientist, Daddi. Dr. Oscar Riddle of Chicago Univer- 

 sity was one of the first to continue with color work. It was through the 

 incentive of an address by him before the zoological meeting at Chicago, 

 1907-8, that the feeding of color dyes was begun at Cornell University. 

 Dr. Gage, Professor of Histology and Embryology, with the Department 

 of Poultry Husbandry in co-operation, started several experiments of feeding 

 Sudan III to hens. 2 The work has since been continued by the writer, using 

 other dyes in addition to Sudan III. 



THE NATURE AND ACTION OF THE DYES 



Sudan III is a common aniline dye, a compound from Amidoazobenzene 

 and B. Napthol. It is soluble in alcohol, ether, benzene, petroleum, ether, 

 oils and fats. When fed to fowls it apparently colors the fat deposits only. 



In the experiments with Sudan III, 25 mg. of the dye were fed to a 

 mature fowl each day. Although smaller amounts produced color, this was 

 not sufficiently intense. Larger amounts may be fed without injuring the 

 fowl. Dr. Riddle has shown, however, that excessive amounts produce 

 fault-bars in the growing feathers of Barred Plymouth Rocks. 3 



Another aniline dye that produces striking results is Rhodamine Red. 

 It is fed to a mature fowl in doses of 100 mg. each day. It colors the body 

 muscles, the feathers which are being grown when the dye is in the blood, 

 and the shell and albumen of the egg. 



It should be borne in mind that Sudan III colors the yolk of the egg 

 only, while Rhodamine Red colors the albumen strongly and the yolk 

 slightly. 



The other dyes used were Auramine Yellow and Saffranine Red. These, 

 as far as the work progressed seemed to act in much the same way as the 

 Rhodamine Red. 



There have been no injurious results noticed except in one instance. 

 The fowl fed Auramine Yellow steadily lost in weight, but regained weight 



Reprinted from the Cornell Countryman. 



2 Science 1908, N. S., Vol. XXVIII, No. 719, p. 494, "Sudan III Deposited in the 

 Egg and Transmitted to the Chick." 



3 Biological Bui. No. 6, May, 1908, Vol. XIV, "The Genesis of Fault Bars in Feathers 

 and the Cause of Alternation of Light and Dark Fundamental Bars." 



