THE SKIN AND ITS SECRETIONS. 325 



that it does contain iron. MORNER found for this coloring mat- 

 ter from tumors (A) and from urine (B) the following composition 

 calculated on the substance considered as ash-free : 



A B 



C 55.3256.13 55.76 



H 5.65 6.33 5.95 



N 12.30 12.27 



S 7.97 9.01 



Fe 0.063-0.081 0.20 



NENCKI and SIEBER have also shown that other melanins, not 

 identical with phymatorusin, occur in melanotic sarcoma of man. 



The coloring matter or matters of human hair contain a low 

 amount of nitrogen, 8.5$ (SIEBER), and a variable but high amount 

 of sulphur, 2.71-4.10$. The considerable quantity of iron oxide 

 found in the ash does not seem to belong to the coloring matters. 



In addition to the coloring matters of the human skin we may also here 

 treat of the pigments found in the skin or epidermis-formation of animals. 



The beautiful color of the feathers of many birds depends in certain cases 

 on purely physical causes (interference-phenomena), but hi other cases on col- 

 oring matters of various kinds. Such a coloring matter is the amorphous red- 

 dish-violet turacin, which contains copper, and whose spectrum is very similar 

 to that of oxyhsemoglobin. KRUKENBERG found a large number of coloring 

 matters in birds' feathers, namely, zooerythrin, zoofulvin, turacoverdin, zoom- 

 bin, psittacofulmn, and others which cannot be enumerated here. 



Tetronerythrin, so named by WURM, is a red amorphous coloring matter 

 which is soluble in alcohol and ether, and which occurs in the red warty 

 spots over the eyes of the heath-cock and the grouse, and which is very widely 

 spread among the invertebrates (HALLIBURTON, DE MEREJKOWSKI, MACMUNN). 

 Besides tetronerythrin MACMUNN found in the shells of crabs and lobsters a 

 blue coloring matter, cyanocrystallin, which turns red with acids and by boiling 

 water. Hcematoporphyrin, according to MACMUNN, also occurs in the integu- 

 ments of certain lower animals. 



In addition to the coloring matters thus far mentioned a few others found 

 in certain animals (though not in the skin) will be spoken of. 



Carminic acid, or the red coloring matter of cochineal, has the composition 

 CnHjeOio. It gives sugar on boiling with acids, but this does not correspond 

 -with the recent statements of LIEBERMANN. The beautiful purple solution of 

 ammonium carmiuate has two absorption-bands between D and E which are 

 similar to those of oxyhaemoglobin. These bands lie nearer to E and closer 

 together and are less sharply defined. Purple is the evaporated residue from 

 the purple- violet secretion, caused by the action of the sunlight, from the so- 

 called " purple gland " of the tunic of certain species of murex and purpura. 

 Its chemical nature has not been investigated. 



Among the remaining coloring matters found in invertebrata we may men- 

 tion blue stentorin, actiniodirom, bonellin, polyperythrin, peniacrinin, ante- 

 donin, cru8taceorubin,janthinin, and chlorophyll. 



