194 CAROTINOIDS AND RELATED PIGMENTS 



the skin of infants can be colored with carotinoids by feeding diets 

 rich in carotin or xanthophyll, and that this was accompanied by an 

 increased lipochrome content of the blood serum. The latter was 

 identified as carotin in the case of carrot feeding. Hess and Myers 

 state that the skin pigmentation resulted in infants "when the dietary 

 included two oranges a day, or the yolk of one egg in the milk formula 

 for a period of two months, or two ounces of spinach daily for a 

 month," as well as when the equivalent of two tablespoonfuls of fresh 

 carrots was fed each day for a period of four to six weeks. An in- 

 crease in the carotin content of the blood serum was also noted fol- 

 lowing a subcutaneous injection of carotin (from carrots) dissolved in 

 olive oil, and the pigment also appeared in the urine. The latter phe- 

 nomenon was noted also when a concentrated carotin solution in olive 

 oil was given to an infant by mouth. 



The general fact that man and the higher mammals and the fowls 

 derive the chromolipoids of their tissues and secretions from the caro- 

 tinoids of their food is now well established. Van den Bergh, 5 Muller 

 and Broekmeyer (1920), especially, have contributed much valuable 

 data on the variations in the carotinoids in the human body under 

 normal and diseased conditions, as well as contributing observations 

 on the character and extent of the carotinoid pigmentation in various 

 species of animals. The numerous reports of the skin coloration's of 

 diabetics, known as Xanthosis, Carotinemia, Lipochromemia, etc., 

 which were cited briefly in Chapter IV, also support and confirm the 

 biological relationship between plant and animal carotinoids, at least 

 for the higher animals. Since this has already been demonstrated 

 to be the case for the phytophagous insects there seems to be no valid 

 reason for rejecting the general thesis that all animal lipochromes 

 are derived from the carotinoids of the food. This conclusion must 

 be accepted for the herbivorous animals of all species, both vertebrates 

 and invertebrates, in which lipochromes are found. When one con- 

 siders that those animals which prey solely on lower forms of animal 

 life usually, if not always, select their food among species which are 

 herbivorous, then the possibility becomes practicable, if not demon- 



1 In this paper van den Bergh lays claim to an unpublished study carried out by him 

 in 1913 in which he showed that the lipochrome content of the blood serum of men, 

 fowls and cattle, as well as the milk of the latter varies with the lipochrome content 

 of their food. In his splendid paper with Snapper (see van den Bergh and Snapper 

 [1913]) on the lipochrome of the blood serum of man, horses and cattle, he shows 

 unmistakably, however, that he regarded the pigment as originating in the body, 

 although he does raise the question as to the origin of the high pigmentation which he 

 observed in the case of diabetics. 



