330 MISSOURI AGR. EXP. STA. RESEARCH BULLETIN No. 9. 



The Physiological Relation Between Plant and Animal Lipochromes. 



With the review of the chemical side of this problem complete, 

 it yet remains to consider what has been shown in regard to relations 

 other than chemical, between the animal and plant pigments whose 

 properties are so nearly related and in many cases identical. 



The literature has been found to be very brief on this point. 

 Newbigin 1 gives a rather extensive consideration of this subject and 

 attempts to explain the presence of the red and yellow pigments found 

 by him in the salmon organism. While he considered the most obvious 

 explanation to be that they were derived directly from the food, he 

 found a number of difficulties in the way of the acceptance of such 

 an explanation, the most important of which was that he was able 

 to show the presence of but a trace of only the yellow pigment in the 

 usual food of the salmon, 



As to the possibility of transference of yellow pigments from 

 one organism to another, Newbigin points out what he believes to be 

 some evidence apart from the case of the salmon. He says, "Poulton 2 

 has shown by experiment that certain caterpillars derive their pigments 

 from their food. Again it is not uncommon to find fat of sheep and 

 cows dyed a deep yellow color. According to some authorities this 

 occurs quite sporadically without known cause, while according to 

 others, special foods, notably maize, are the important agents." New- 

 bigin says in this connection, "I have examined the yellow pigment of 

 maize, and compared it with the pigment from yellow fat. The maize 

 pigment gives the lipochrome reaction faintly with H 2 SO 4 distinctly 

 with HNO 3 while the fat pigment gives no lipochrome reaction. In 

 other respects, in tint, solubility, etc., the pigments closely resemble 

 each other." Newbigin did not feel warranted to conclude from these 

 experiments that all yellow pigments of animals are derived from 

 their food, for with such a conclusion, he states, "It would be difficult 

 to understand why such colored fat should not be universal in herbivor- 

 ous animals, for all green parts of plants contain also a certain amount 

 of yellow pigment." 



It seemed to Newbigin, however, that a reasonable explanation for 

 salmon, domesticated cattle and caterpillars would be to suppose that 

 when they ingest a moderate amount of colored fat in their food, 

 that they could utilize or eliminate the pigment, and so deposit colorless 

 fat in the tissues ; but when the ingestion of colored fat is in excess 

 of the actual requirements as it so often is, especially with domes- 



1. Loc. cit. 



2. Proc. Roy. Soc. 54, p. 417; Nat. Sci. 8, p. 98. 



