324 PHYSIOLOGICAL CHEMISTRY. 



the black or brown pigment occurring in the hair oelong to the 

 group of coloring matters which have received the name melanin. 



Melanins. This group includes several different varieties of 

 amorphous black or brown pigments which are insoluble in water, 

 alcohol, ether, chloroform, and dilute acids, and which occur in 

 the skin, hair, epithelium -cells of the retina, in sepia, in certain 

 pathological formations, and in the blood and urine in disease. Of 

 these pigments there are a few, such as the melanin of the eye 

 and that from the melanotic tumor of horses, the hippomelanin 

 (NENCKI and BERDEZ), which are soluble with difficulty in alkalies, 

 while others, such as the pigment of the hair and the coloring 

 matter of certain pathological swellings in man, the pliymatorusin 

 (NENCKI and BERDEZ), are easily soluble in alkalies. 



Among the melanins there are a few, for example the choroid 

 pigment, which are free from sulphur; others, on the contrary, as 

 the pigment of the hair and of horse-hair, are rather rich in sul- 

 phur (2-4$), while the phymatorusin found in certain swellings 

 and in the hair (NENCKI and BERDEZ, K. MORNER) is very rich in 

 sulphur (8-10$). If any of these pigments, especially the phyma- 

 torusin, contains any iron or not is an important though disputed 

 point, for it leads to the question whether these pigments are formed 

 from the blood-coloring matters (NENCKI and SIEBER, K. MOR- 

 NER). The difficulties which attend the isolation and purification 

 of the melanins have not been overcome in certain cases, while in 

 others it is questionable whether the final product obtained has not 

 another composition than the original coloring matter, owing to 

 the energetic chemical processes resorted to in its purification. 

 Under such circumstances it seems that a tabulation of the analy- 

 ses of different melanin preparations made up to the present time 

 are of secondary importance. 



Among the above-mentioned bodies belonging to the melanin 

 group, phymatorosin prepared by NENCKI and SIEBER from mel- 

 anotic tumors, and by K. MORNER from the tumors and" the urine 

 of a patient, seems to be of special interest. Phymatorusin is an 

 amorphous dark-brown coloring matter soluble in alkalies or alkali 

 carbonates, but insoluble in warm 50-75$ acetic acid. In alkaline 

 solution it shows no absorption-bands. According to NENCKI and 

 SIEBER, it is free from iron, but MORJJER, on the contrary, claims 



