Suda}i III in Metabolism and Inheritance 1 75 



in peritoneal fat. On the other hand, the muscles showed extreme 

 waste. Two of the birds from the other pen were now sacrificed 

 for comparison. They showed hardly a trace of fat. Dipping 

 them into an eighty per cent alcoholic solution of Sudan failed to 

 reveal more than traces. The muscles, however, were obvioulsy 

 larger and much better preserved than in any of the Sudan-fed 

 birds. Sudan w^as found to be a non-toxicant as many birds were 

 fed several months and one adult hen was fed the stain almost 

 continously for ten months without visible injurious effect. This 

 fact, together with those mentioned above, lead one to suspect 

 that the presence of the stain in the fat made this fat in these birds 

 less available than if unstained, and that under the new conditions 

 the energy of the proteins (of the muscle, etc.) became more avail- 

 able than that of the fats. 



(3) If birds be fed considerable quantities of Sudan while 

 growing a plumage it will be found that the "fault-bars"^ of the 

 feathers become more pronounced in extent. It has been shov/n 

 conclusively that any decrease in the nutrition of the feather germs 

 produces these effects. Attention has elsewhere (Riddle, '07° p. 

 172) been specifically called to this power of Sudan to produce 

 fault-bars or defective areas in feathers and to the fact that this 

 seems to be due to a starving effect produced by the Sudan. 



(4) It has also been pointed out by the writer (08, p. 174) that 

 if young chicks in their downy plumage be "starved" for a time, 

 or fed Sudan in quantities, there is a common result in the two 

 cases, namely, an inhibition of the growth of most of the definitive 

 feathers and a long retention of the downy plumage. This is 

 evidence of the sort we are just now examining, since these Sudan 

 effects so closely parallel "starving" effects. The following case 

 is perhaps less valuable evidence of the same kind. 



(5) It has been observed that many laying hens cease to lay 

 eggs after having been fed considerable quantities of the stain. 

 The effect here is again the same as that resulting from a with- 

 drawal of food; it may, however, have other causes as well. 



(6) The above and similar observations led to the following 

 experiments. The one here recorded was made after nos. 7 and S 



■• See Oscar Riddle on the Genesis of Fault-bars in Feathers and the Cause of Alternation of Light 

 and Dark Fundamental Bars. Biol. Bull., vol. 14, pp. 32S-37C, 1908. 



