BIOLOGICAL RELATIONS BETWEEN CAROTINOIDS 187 



bility of transferring carotinoid pigment from plants to animals, or 

 which were designed to determine whether any of the normal pigments 

 of animals arc merely derived from the food. 



The earliest, as well as the most interesting experiment of this 

 kind, so far as carotinoids are concerned, was conducted by Sauermann 

 (1889) who studied the effect of feeding cayenne pepper to birds. He 

 became interested in the problem because of the custom in vogue at 

 that time of coloring the feathers of canary birds by feeding them red 

 pepper. It is stated in the paper that the canary bird dealers who 

 practiced this artificial coloring mixed the cayenne pepper with egg 

 yolk and bread and fed the mixture to the very young birds or to old 

 birds during the molting season, thereby coloring the new feathers 

 a yellow to red color. When Sauermann tried the experiment using 

 the red pods from which the pepper but not the pigment had been 

 extracted with 60 per cent alcohol, the pepper plants had scarcely any 

 effect on the color of the plumage. The same result followed the feed- 

 ing of the crude pigment which had been extracted with absolute 

 alcohol, but when this extract was dissolved in sunflower oil the re- 

 sults reported by the canary bird dealers were confirmed. 



Especially interesting were Sauermann's experiments on feeding the 

 pepper pigment to fowls. In this case the cayenne pepper itself was 

 fed to 12 white Italian fowls, 8 weeks old, the young chickens being 

 fed 25 grams of the pepper night and morning mixed with moistened 

 bread and potatoes. The birds received corn and oats in addition. It 

 is stated that the feet of all the fowls became orange and that the 

 pepper pigment could be extracted from them by soaking them in 

 alcohol for a long time and then extracting with ether. No proof is 

 given for the fact that the pigment extracted in this manner was the 

 pepper pigment. Only two of the 12 fowls showed any effects of the 

 pepper feeding on the feathers. The pigment began to appear on the 

 breast of one hen in about 10 days and the other in about 3 weeks. 

 The first hen eventually developed a red breast and the rest of the 

 body became yellowish red, but the second hen only developed red 

 feathers on the breast, the rest of the body remaining white. Old hens 

 were not influenced in the least by pepper-feeding, even during the 

 molting season. If the pigment which appeared on the feathers of 

 the two young birds was the red pepper pigment, it is difficult to 

 understand why none of the other young birds were affected, or why 

 the old hens did not develop some tint in the new feathers formed 

 during the molt. 



