400 THE MILK OF MAMMALS OTHER THAN THE COW. 



per cent, ash, the nitrogen calculated to the pure substance being 

 14'66 per cent, and the phosphorus 0"85 per cent. Other pre- 

 parations, which were less pure, gave about 14:'4 to 14'5 per 

 cent, of nitrogen. 



Though this casein was precipitated three times, and thor- 

 oughly washed with water each time, and finally with alcohol and 

 ether, it was perhaps not pure, as a solution was made in a mini- 

 mum of caustic soda, and equivalent amounts of sodium phos- 

 phate and calcium chloride added, and the nitrogen was estimated 

 in this and in the precipitates obtained by (1) saturation with 

 magnesium sulphate, (2) tannin, and (3) acetic acid at 40° C. 



Calling the nitrogen in solution 100, the following amounts 

 were obtained by 



Magnesium sulphate, ..... 95-2 



Tannin, 96-6 



Acetic acid, ....... 94-7 



Albumin. — The albumin contained 1575 per cent, of nitrogen, 

 and is probably identical with that of cow's milk. 



Citric acid was identified by isolating it and determining the 

 percentage of calcium in the calcium salt. 



A yellow crystalline mercury compound was isolated from 

 the winter milk in too small a quantity for identification, 

 but was in all probability derived from a nitrogenous basic 

 substance. 



Sugar. — The sugar was prepared from the winter milk. Two 

 preparations gave the following figures : — 



Influence oti r i Cupric reducing Water of 



density. L h^. power. crystallisation. 



.3-94 48-66 73-6 4-77 



3-94 49-10 73-9 4-82 



Mucic acid was not obtained by oxidation with nitric acid. 

 On treatment with acid the following figures were obtained :— 



L<^Jp Cupric reducing power. 



53-74 101-0 



figures approaching those given by dextrose. 



This sugar evidently differed from milk-sugar, and was named 

 " Tewfikose." 



A second preparation was made from the summer milk ; it 

 was examined by A. R. Ling and the author, and yielded the 

 following figures. (For the sake of comparison figures yielded 

 by milk-sugar, prepared by the same method, are given.) 



