BIOLOGICAL RELATIONS BETWEEN CAROTINOIDS 185 



authorities, this occurs quite sporadically without known cause, while 

 Mi-cording to others special foods, notably maize, are the important 

 agents." Miss Newbigin then states that she secured the lipochrome 

 color reactions with the maize pigment but not with the pigment from 

 yellow fat. "In other respects, in tint, in solubility, and so on, the 

 pigments closely resemble each other. This fact, taken in combination 

 with Mr. Poulton's experiments, seems to me at least to prove the 

 possibility of the transference of these pigments from one organism 

 to another, and therefore to suggest such an origin for the yellow pig- 

 ment of the salmon." 



On further consideration Miss Newbigin concluded that the deriva- 

 tion of yellow pigment from the food could not be very general, other- 

 wise pigmented fat would be universally found in herbivorous animals, 

 which Miss Newbigin knew is not the case. Her explanation of the 

 phenomenon which she believed to be peculiar to caterpillars, salmon 

 and domesticated cattle was that they ingested more colored fat in 

 their food than they required with the result that, "fat colored with 

 the pigment in more or less modified condition is deposited in certain 

 of the tissues." 



Miss Newbigin's views are quoted at some length because they not 

 only have a direct bearing on some of the experiments of Palmer and 

 Eckles, but they are the most definite of any of the earlier views on 

 the subject of a possible general origin of animal lipochromes from 

 plants. Although Miss Newbigin decided against any such general 

 relationship between plant and animal pigments the writer has found 

 several isolated observations which support the idea when viewed in 

 the light of our present knowledge. These may be mentioned briefly. 



Schneider (1799) observed a great many years ago that the toad, 

 Bujo viridis, loses its green color on wintering in the earth. Von 

 Wittich (1854) noted that the frog, Rana esculenta, took on a grayish- 

 brown instead of its usual green color after long fasting and that this 

 was accompanied by a disappearance of the yellow cells in the tegu- 

 ment. The disappearance of the lipochromes from the skin of fasting 

 frogs was confirmed by Hering and Hoyer (1869), who also noted its 

 slow reappearance when the animals were given their usual food. Bate 

 and Westwood (1869) stated that the color of Idotea is influenced by 

 the food, in that animals which eat Fucus are dark or black, while 

 those which eat green algae are green. This statement, however, has 

 been denied by Mobius (1873) and Matzdorff (1883). Beddard 

 (1892) cited the observation of Eisig that certain marine worms be- 



