Sudan III in Metabolism and Inheritance 169 



in the somatic structures of larvae hatched from such eggs. The 

 writer ('07) caused birds and turtles to deposit quantities of 

 Sudan within their eggs. S. H. and S. P. Gage ('08) have 

 hatched Sudan-containing eggs of the fowl and noted the re-dis- 

 tribution of the stain in the somatic tissues. In addition to these 

 cases, however, it should be noted that it is practically certain 

 that the natural coloring matter of the eggs of the salmon pro- 

 ceeds from the muscles of the fish. It is quite certain that the 

 fat which is in these muscles, and in which much if not all of the 

 coloring matter resides, is transferred to the ovary and to the 

 growing eggs. These lipochromes of the muscle fat doubtless 

 remain fixed to the constituent fatty acids, when this fat is broken 

 up in the muscles and is thrown into the circulation; from the 

 blood or lymph, we believe, the two enter the ovum together, 

 precisely as in the case of Sudan-stained fat. 



EXPERIMENTAL METHODS 



Laying hens were fed Sudan III in three ways, viz.: in gelatine 

 capsules, dissolved in egg-yolk, butter or animal fat, or by enclos- 

 ing small lumps of tfie stain in pieces of bread (no fat). The 

 results were very similar in all cases. With birds, the method of 

 feeding seems quite immaterial since the stain apparently always 

 m.eets with enough fats within the alimentary canal to carry con- 

 siderable quantities of it through the intestinal wall. The dose 

 varies from one-half 2ram to three milligrams. For most studies, 

 particularly those dealing with problems of metabolism, large 

 doses are to be avoided; from three to twenty milligrams have 

 been found most useful, Many birds were fed the stain at inter- 

 vals of thirty-six, forty-eight and seventy-two hours; series of 

 eggs from birds thus fed were obtained, were hardboiled, sectioned 

 under water with a sharp razor and then examined, these latter 

 operations being done chiefly to learn the rate of growth of the 

 ova. In other cases the birds were killed at such time after feeding 

 as was demanded by the points under investigation. 



The stain was introduced into the bodies of chicks and rabbits 

 also by injection of its solution in a mixture of oleic acid and 

 alcohol. A w^idely variable quantity of the solution was injected 



