THE PROTEIN MOLECULE 91 



sources cannot be questioned. Its effects on 

 animals have been widely tested and the gen- 

 eral conclusions reached are quite as uniform 

 as those which might be formulated about poi- 

 sons much longer known. Its chemical struc- 

 ture has not been determined with certainty. 

 The best evidence at hand today seems to indi- 

 cate that it is not a basic body, and therefore 

 not a protein alkaloid, not a leucomain or a 

 ptomain. It contains no phosphorus and no 

 carbohydrate. In the purest form in which it 

 has been obtained, it yields a trace of ash of 

 which phosphorus and chlorine are not essen- 

 tial constituents. Whether this mineral matter 

 is an essential part of the poison or not, I do 

 not know. Under any condition in which it has 

 been obtained it is decidedly acid in character 

 and yields amino acids on disruption. It seems 

 to be a polypeptid. 



Underbill, whose opinion I esteem highly, 

 concludes that the action of the protein poison 

 on animals is similar in kind but more intense 

 than that of proteoses. I dare say that this is 

 quite right and it conforms with my own ob- 

 servations. I suggested in the Shattuck lec- 

 tures in 1906 that the protein poison is the 

 chemical nucleus, keystone, or archon of larger 

 and more complicated protein molecules. 



