24 POISONOUS PROTEINS 



cent sodium hydroxide ; besides he did not test 

 this residue for nitrogen but seems to have as- 

 sumed that this element was not present since 

 the body did not respond to the protein reac- 

 tions. In our tests this body remained in the 

 residue after heating for one hour at 120 with 

 ten per cent potassium hydroxide, and did not 

 give the protein reactions, but did contain ni- 

 trogen. We know of no nitrogenous carbohy- 

 drates except the chitins. 



Tamura reports a negative test for sulphur in 

 bacterial proteins, but this is due to faulty tech- 

 nic, since Wheeler has shown that the sulphur 

 is masked and does not respond to the ordinary 

 tests, but its presence is disclosed when a por- 

 tion of the substance is fused with metallic so- 

 dium, dissolved in water and treated with a 

 freshly prepared solution of sodium nitroprus- 

 siate ; a violet color indicating the presence of 

 sulphur. 



While the "acid-fast" and "Gram-positive" 

 properties of certain bacteria depend upon lip- 

 oids which are extracted from the cells by al- 

 cohol and ether, the cells, after exhaustive ex- 

 traction with these solvents, take the analin 

 dyes quite as well or even better than before. 

 For instance, the extracted tubercle bacillus 

 stains just as well, or even better, than before 



