184 CAROTINOIDS AND RELATED PIGMENTS 



referred to do not feed upon these plants, they devour in immense 

 quantities the invertebrate animals inhabiting the same region, many 

 of which are likewise deeply tinged with red. Possibly the blacks and 

 greens which prevail among the inhabitants of other colored bottoms 

 are likewise dependent upon coloring matter which is absorbed with 

 the food. Giinther believes that the pink color in the flesh of the 

 salmon is due to the absorption of the coloring matter of the crus- 

 taceans they feed upon." 



Miss Newbigin, both in her papers (1898) and her Monograph 

 (1898) takes a somewhat intermediate position on the 'question of 

 derived animal pigments. Regarding insects, she accepts Poulton's 

 results but qualifies them by stating that, "At the same time there is 

 no apparent reason why insects should not themselves produce lipo- 

 chromes, and why such lipochromes should not occur in the cuticle 

 as in the Crustacea." With reference to the carotinoids in birds, she 

 states with more conviction, that "although there are several instances 

 described of birds whose colors can be heightened or altered by the 

 employment of special kinds of food, there is at present no reason to 

 doubt that under ordinary circumstances the lipochromes of birds 

 are self-produced and not derived." 



Miss Newbigin gives a more extensive presentation of her views on 

 this subject in her paper on salmon pigments (1898). It will be re- 

 called that she found a rod lipochrome and a yellow pigment which 

 she could not identify as a true lipochrome in the muscle and ovaries 

 of this fish. In discussing these findings she states, "The most obvious 

 explanation is that the pigments of the salmon are derived directly 

 from its food. ... At first sight the suggestion has much to recom- 

 mend it. ... There are, however, some difficulties in the way of the 

 acceptance of this suggestion. In the first place, the salmon seems to 

 feed chiefly on haddock, herring, and similar fish, so that the transfer 

 of pigment can hardly be direct. The herring, however, feeds habitu- 

 ally on small Crustacea, so that it might be said that the pigments of 

 the salmon are obtained indirectly from herring which forms its food." 

 Miss Newbigin, however, was unable to find the red pigment in her- 

 ring, but did find a small amount of the yellow pigment in the viscera 

 and muscles. In support of the general proposition of animal lipo- 

 chromes being derived from the food Poulton's experiments are first 

 cited and then the fact that, "it is not uncommon to find the fat of 

 sheep (?) x and cows dyed a deep yellow color. According to some 



1 Question by author. 





