116 PROTEIN POISONS 



Leach split up edestin, casein, egg-white, and colon 

 cellular substance with alkaline alcohol. The insoluble 

 part of each gave the various protein color tests, Millon's 

 reaction less satisfactorily than the others. On stirring 

 with water, the edestin preparation was entirely soluble, 

 there was a slight flocculence with the casein preparation, 

 the others were mainly but not wholly soluble. Addition of 

 a little sodium hydroxide increases the solubility. Mineral 

 acids give precipitates with the casein and egg preparations. 



The most marked difference was found on testing for 

 carbohydrates. As edestin contains no carbohydrate, its 

 preparation showed no evidence of such a group. Although 

 casein is said to contain no carbohydrate, it has been found 

 to respond to the Molisch test, and so does its haptophor. 

 As was to be expected, the egg preparation gives evidence 

 of hexose and not pentose. The lead sulphide reaction 

 shows the presence of loosely combined sulphur in the 

 preparations from egg and edestin, not in the ones from 

 casein and the colon bacillus. 



Samples of the haptophor of egg-white were stirred with 

 water, filtered, and attempts made to separate protein and 

 carbohydrate in the filtrate by means of uranium acetate. 

 The acetate was added both with and without sufficient 

 alkali to keep the solution alkaline. A copious precipitate 

 resulted in both cases and this was filtered out with some 

 difficulty. The slight excess of uranium was removed 

 from the filtrate by the addition of sodium phosphate. 

 The filtrate gave evidence of carbohydrate, but the separa- 

 tion was not sufficiently sharp, and that method was 

 abandoned. Acidifying until there was a slight permanent 

 precipitate, the addition of either ethyl or methyl alcohol 

 cleared the solution. Phosphotungstic acid precipitated 

 both protein and carbohydrate. In short, no method was 

 found that would remove the protein from the solution and 

 leave the carbohydrate. It is perhaps a legitimate infer- 

 ence that the combination of the two is a chemical one. 



Samples were subjected to hydrolysis and titrated with 

 Fehling's solution. The proteins and possibly other bodies 



