44 CHEMICAL CONSTITUENTS OF BODY AND FOOD. 



precipitated is filtered off. The filtrate is allowed to stand at the 

 temperature of the air, and as it gets concentrated minute spheroidal 

 globules of varying size, and finally minute needles, either aggregated or 

 separate, make their appearance (Fig. 9). On examining these crystals, 

 they are found to consist of egg albumin, with a variable (but usually 

 small) admixture of ammonium sulphate. Serum albumin has similarly 

 been obtained by G-iirber and Michel, 1 in a crystalline form, from the 

 blood serum of horses and rabbits. More recently still, caseinogen has 

 been crystallised. When a solution of this substance is mixed with 



FIG 9. Crystals of egg albumin. 



ammoniacal magnesia mixture, it proceeds after some days to deposit 

 sphreroliths, and ultimately aggregations of needle-like crystals. They 

 contain 45 per cent, of ash, and 14'98 per cent, of nitrogen. Nuclein 

 also yields a crystalline deposit with ammoniacal magnesia mixture 

 (v. Moraczewski). 2 



Byrom Bramwell and Noel Paton 3 have described a case of albuni- 



1 Sitzungsb. d. phys.-med. GeseUsch. zu Wurzburg, 1894. Michel (ibid., No. 3, B<K 

 xxix.; Centralbl.f. d.' med. Wissensch., Berlin, 1896, S. 152) gives full details of the method 

 employed. The crystals are hexagonal prisms with the following percentage composi- 

 tion : C, 53-1 ; H. 7-1 ; N, 15'9 ; S, 1'9 ; 0, 22'0 ; ash, only 0'22. They coagulate at 

 51 -53 C. () D = -61. 



2 Ztsclir. f. physiol. Chem., Strasshurg, Bd. xxi. S. 71. 



3 Hep. Lab. Roy. Coll. Phys., Edinburgh, 1892, vol. iv. p. 47. 



