174 Oscar Riddle 



body of animals not depositing fat, without coloring certain regions 

 of fat. (4) It was found that within the ovum the Sudan is de- 

 posited in the germinal disc and in the latebra in smaller amounts 

 than elsewhere. This is undoubtedl) to be associated with the 

 lower fat content of these regions of the egg. 



AN UNSUSPECTED ACTION OF SUDAN 



Ju Apparent Tendency of Sudan to Lessen the Availability of 

 Fats in the Organism. Since 1904, when the writer first fed Sudan 

 to chicks, several things have come under his observation which 

 indicate thRtSiidan-stamedfatis not as available, — does not split up 

 and yield its energy to the organism as readily — as does the unstained 

 fat. If this could be positively established it would be a very im- 

 portant fact, possibly giving some clue as to what "availability" of 

 foods rests upon. We might, perhaps, then proceed so to treat 

 certain foods or constitutents of the tissues as to increase or 

 decrease at will their utilization or destruction within the body. 



Some special effort has been made to get positive data on this 

 hitherto unsuspected action of Sudan. It must be admitted that 

 conclusive data have not been obtained; in their absence the writer 

 can only submit the following record of efforts, — a few observations 

 and experiments which seem to contain some bits of evidence: 



Biological Evidence 



(i) Young chicks which were given Sudan with their food ate 

 much more than those not fed the stam; they seemed always 

 hungry and did not grow as well as the other birds of the same age 

 and breed. This, of course, may easily have another explanation 

 than the one suggested. 



(2) In a certain "starving" experiment it happened that birds 

 three months old were used, five of which had been given three 

 heavy feedings of Sudan during the two days immediately preced- 

 ing the starving period. These five Sudan-fed birds were all dead 

 before any of the four r.on-fed ones showed very great signs of 

 weakness. Three of the five dead birds were carefully examined. 

 They showed Sudan in patches of subcutaneous fat, in other 

 patclies along the neck, behind the occiput and even distinct traces 



