46 POISONOUS PROTEINS 



have an unmixed protein. It is a single com- 

 pound, of highly complex structure it is true, 

 but not a mixture of different molecules. If the 

 poison be detached from this by chemical cleav- 

 age it must follow that the poison consists of 

 a group which exists within the larger body. 

 The importance of this will be more evident 

 when I call attention to the fact that some years 

 ago Pick and Spiro were unable to obtain from 

 edestin the substance which when injected into 

 animals retards the coagulation of the blood 

 and from this failure they concluded that this 

 body is not a true cleavage product of proteins 

 and that it is not an intramolecular constituent 

 of pure proteins. In fact they came to the con- 

 clusion that the coagulation-retarding substance 

 is neither a protein nor a protein derivative. 

 The relation between the protein poison and the 

 coagulation-retarding substance will be dis- 

 cussed later. At this point I simply wish to 

 emphasize my claim that the protein poison is 

 an intramolecular constituent of proteins and 

 that it is obtained by the chemical cleavage of 

 protein molecules. Edestin being a simpler 

 and smaller molecule than bacterial cellular 

 substance is the more suitable matrix from 

 which the protein poison may be obtained. The 

 yield is larger and the by-products less in va- 



