1 70 Oscar Riddle 



into the peritoneal cavities of these animals (also into brachial 

 veins of the chick, and ear veins of the rabbit). The method of 

 feeding the stain to turtles will be described v^nth the results of that 

 work. 



RESULTS OF THE EXPERIMENTS 

 Deposition of Sudan III in Ova 



The eggs of hens fed as described above almost invari- 

 ably showed marked quantities of the pigment deposited in the 

 yolks. An ovum which had undergone its final and rapid growth 

 in a bird which was being fed at regular intervals of thirty-six, 

 forty-eight or seventy-two hours would show in section a series 

 of evenly-spaced, concentric circles of orange-red, these alternat- 

 ing with other circles of light yellow, the natural ground color of 

 the yolk. The width of any Sudan-colored circle could have 

 been regulated at will at the time of feeding; much stain giving 

 the wide rings of red, and little stain resulting in narrower rings 

 of less intense color. If the birds be killed a few hours after 

 feeding all ot the larger ova are found to be deep red on the 

 outside; if, however, the bird be not killed until one or two days 

 have elapsed since the feeding, these ova will have a perfectly 

 normal external appearance, and only an examination of the in- 

 terior of the eggs will reveal the presence of the stain. This is, of 

 course, a consequence of the rapid growth of these ova. 



One successful attempt was made to stain the ova with Sudan 

 injected into the peritoneal cavity. Four injections of a mixture 

 of alcohol and oleic acid forty per cent each, to which traces of 

 sodium carbonate were added, were given within a period of 

 forty-eight hours. Four eggs were subsequently laid by this bird 

 and were found to contain the dye. 



In the case of the turtles the records are as follows: Three 

 very large females of Emydoidea blandingii were heavily fed with 

 Sudan for three weeks during July and August. The stain was 

 put with butter into capsules of large size and these were pushed 

 with long-slender forceps into the stomach, while the neck was 

 stietched and the mouth held open with other forceps. All were 

 killed five days after the last feeding. All of the larger ova 



