90 POISONOUS PROTEINS 



from the disease and when these are trans- 

 ferred to new hosts they show that they have 

 lost nothing in virulence. Frequently, second- 

 ary infections develop and decide the fate of 

 the individual. As someone has said the pyo- 

 genic microorganisms frequently play the last 

 act in the great tragedies of life, tuberculosis, 

 cancer, and syphilis. 



A Chemico-Biologic Concept of the Protein 

 Molecule. 



Under this heading I wish to formulate cer- 

 tain theories which have developed in my mind 

 during the progress of the work which I have 

 outlined in preceding lectures. Some men 

 seem able to work without developing theories 

 and probably this is best, but I have never 

 worked in that way. It is possibly a fault ; if 

 it be, I am ready to confess that I have sinned 

 and continue in the same old way. I hope that 

 some of the statements which I am about to 

 make will stimulate others to investigate and 

 this I deem of more importance than their truth 

 or falsity. 



The protein poison about which all my work 

 has centered is a fact. It has been prepared 

 and studied by so many competent men that its 

 wide distribution in proteins from diverse 



