TI:E MICROBES OF HUMAN DISEASES. 241 



parasite, which is nourished and multiplies at the 

 expense of the fluids and gases of the system ; (2) the 

 formation by this parasite of a poisonous substance 

 (ptomaine), of which the elements are derived from the 

 organism, and it acts as a poison on this organism. 



i? 



