192 



SCIENCE 



[N. S. Vol. L. No. 1286 



Such findings so aptly provided for an in- 

 tracellular occurrence of lipochrome tliat the 

 working hypothesis for the nerve cell was 

 based on them. The point that first focused 

 our attention on the probable carotinoid 

 identity of nerve cell lipochrome was its ab- 

 sence in the rabbit and dog. The rabbit and 

 dog have colorless fat. Man and cattle, known 

 to show intracellular lipochrome, have colored 

 fat. 



Verification was first sought in the chicken. 

 With the use for the most part of Palmer's 

 chickens above described, two series were run, 

 the one lacking carotinoid containing food 

 from birth, the other carotinoid fed. The 

 carotinoid feeding ranged from a one week's 

 introduction in a bird hitherto carotinoid free 

 to a lifelong natural pigment food in others. 

 In one half of the chickens of both series the 

 factor of depression by heat, phosphorus, 

 morphine or a rice flour diet was introduced 

 to cover the side of disease. 



The results were imcomplicated. Both nor- 

 mal and depressed chickens on any carotinoid 

 diet showed the presence of the characteristic 

 yellow pigment in all nerve cells. The caroti- 

 noid-free chickens lacked such a pigment in 

 demonstrable amount. 



However, this physiological demonstration 

 of the introduction of carotinoid pigment de- 

 mands for completeness the support of micro- 

 chemistry. The question at once arises if the 

 pigment introduced in nervous and other body 

 tissues is identical with the lipofuscin, " wear- 

 and-tear," fat-holding pigment described for 

 the nerve and other somatic cells as specific. 

 While it is true that the micro-chemistry of 

 the lipochrome pigments is superficial, which 

 is the reason that the analysis by that means 

 has hitherto failed, yet it must be emphasized 

 that it has become quite sufScient to demon- 

 strate this identity. The application of this 

 chemistry was more simple in our problem 

 when following a means of providing or with- 

 drawing the pigment at will. The yellow pig- 

 ment introduced in nerve cells and the chicken 

 skin, and the pigment of the carrot in frozen 

 sections give the fat stains, the oxidation and 

 decolorization by hydrogen perosid and ferric 



chlorid, the fat stains after oxidation, and 

 the rapid solubilities in fat solvents in com- 

 mon with a supposed lipofuscin; while the 

 most characteristic test for lipofuscin, the 

 Nile blue stain of Hueck, equally applies to 

 known lipochrome before and after its oxida- 

 tion. This supposed metabolic pigment of the 

 nerve cell is then identical with a true lipo- 

 chrome. 



Finally in corroboration of the species differ- 

 ence in the transferrence of the carotinoid 

 pigment from plants, the cow as well as the 

 chicken exhibits it in nerve cells, while swine 

 with their colorless fat line up with the rabbit 

 and dog in a complete absence. Man, who is 

 best known to exhibit lipochrome, is also 

 known to carry carotinoids in his blood serum, 

 and has colored fat. The consistency is com- 

 plete. 



The lipochrome pigment of the nerve cell is 

 therefore a plant carotinoid, derived from the 

 food, but limited to such species as carry the 

 carotinoids in the blood serum. The concep- 

 tion of it as a " wear-and-tear " pigment 

 falls to the ground with its demonstration as 

 an exogenous and fortuitous pigment. The 

 melanin of the nerve cell is a true metabolic 

 pigment, derived from nuclear materials and 

 produced by chronic depression. Because of 

 this, the conception of a "wear-and-tear " pig- 

 ment is to be transferred to the melanin, as 

 conditioned by agencies without the cell, with 

 a restriction to the abnormal. 



David H. Dolley, 

 Frances V. Gutheie 

 University op Missouri 



SCIENCE 



A Weekly Journal devoted to the Advancement of 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SOENCE PRESS 



LANCASTER, PA. GARRISON. N. Y. 



NEW YORK. N. Y. 



Entered io the pott-^fficc at LanotUr, Pa.» u secood cIms matter 



