530 CHEMISTRY OF THE PROTEIDS CHAP. 



through the solution. When reduced it forms a colourless compound, 

 but when oxidised it exhibits a pure blue. Henze l has analysed 

 hsemocyanin and found its nitrogen to be distributed in the following 

 manner^ 



ammonia- N . . 0'73 1*08 per cent 

 di-amino- N . . 4'34 4'70 per cent 

 mono-amino-N . . 9*50 10 '6 6 per cent 

 hsemin- N . . 0*26 0'66 per cent 



In the mono-amino acid fraction were found leucin, tyrosin, arid 

 glutaminic acid ; while the di-amino acids are represented by lysin 

 and histidin ; arginin could not be demonstrated with certainty, nor 

 could a carbohydrate radical, although hsemocyanin gives a positive 

 reaction with Molisch's test. 



According to Krukenberg 2 hsemocyanin shows no absorption 

 bands. The oxygen capacity has not yet been determined, but is, 

 according to Henze, less than that of hemoglobin. Hsemocyanin is 

 the only albuminous substance found in the blood of cephalopods, and 

 it subserves respiratory purposes. Halliburton 3 has given a list of 

 animals in which hsemocyanin has so far been found. 



PHYCO-ERYTHRIN, the red colouring matter met with in certain 

 seaweeds, the Floridese, frequently crystallises out at the death of the 

 cells. Molisch 4 first recognised its albuminous character ; he isolated 

 it, and succeeded in getting it to crystallise from its solutions. 



PHYCOCYAN is a similar, blue colouring matter found in the Cyano- 

 phyceas. It was obtained in crystals belonging to the monoclinic 

 system by Molisch, 5 who employed Hofmeister's method of fractional 

 salting out. The crystals give the Millon and xanthoproteic reactions ; 

 they are converted by alcohol into pseudomorphoses, and unite with 

 acid and basic dye-stuffs. 



COLOURING MATTER FROM THE FINS OF CRENILABRUS PAVO. 

 v. Zeynek 6 has observed in the fish Crenilabrus pavo a blue colouring 

 matter during the spring time. He has isolated it and shown it to be 

 an albuminous compound. 



II. THE GLYCO- PROTEIDS 



The glyco-proteids are albuminous substances, amongst the dissocia- 

 tion-products of which is found a carbohydrate or the derivative of a 

 carbohydrate. 



1 M. Henze, Zeitschr. f. physiol. Chem. 43. 290 (1904). 



2 F. C. W. Krukenberg, Zentralb. /. d. med. Wiss. 1880, No. 23. 



3 W. D. Halliburton, Journ. of Physiol. Q. 300 (1885). 



4 H. Molisch, Bot. Zeitschr. 1894, p. 177. 5 H. Molisch, ibid. 1895, p. 131. 

 6 Pu v. Zeynek, Zeitschr. f. physiol. Chem. 34. 148 (1901); 36. 668 (1902). 



