PTOMAINS 131 



appear, and the active stage of the disease marks the period over which 

 the parenteral digestion of the foreign protein extends. These specific 

 ferments split up the foreign protein and liberate the toxic portion or the 

 protein poison; this poison is not a toxin and is not specific, but occurs 

 commonly in all proteins. 



The characteristic symptoms and lesions caused by the various 

 infectious processes are determined largely by the location of the foreign 

 protein. The poison elaborated is the same in all infectious diseases, 

 and it is the location of the infection, rather than the exact nature of the 

 infecting agent, which gives rise to the more or less characteristic symp- 

 toms and lesions of the several infectious diseases. 



Death may be produced by the too rapid breaking-up of the foreign 

 protein, and the consequent liberation of a fatal dose of the protein 

 poison, or it may result from a lesion induced by the products of this 

 disruption, such as perforation of the intestine and hemorrhage in 

 typhoid fever, or it may follow from chronic intoxication and consequent 

 exhaustion. If recovery takes place, the individual enjoys an immunity 

 of variable duration, owing to the presence of specific ferments capable 

 of destroying the particular substrata if infection should occur. 



It is this power of body-cells, when permeated by a foreign protein, 

 to elaborate a specific antiferment by which the protein is destroyed, 

 that, in the opinion of Vaughan, forms the basis of a correct understand- 

 ing of infection and immunity. 



PTOMAINS 



It was at one time believed that the symptoms of many diseases 

 were due to the absorption of soluble basic nitrogenous substances pro- 

 duced by bacterial action upon various albumens, these toxic, alkaloid- 

 like substances being known as ptomains. It was soon found, however, 

 that the ptomains produced by pathogenic bacteria were insufficient of 

 themselves to cause the symptoms and lesions characteristic of the re- 

 spective microorganisms; that they were in general less toxic than the 

 cultures themselves; that the majority of ptomains are not very poison- 

 ous; and that they are not specific, since equally potent ptomains are 

 produced by non-pathogenic bacteria. This lack of specificity is in 

 sharp contrast to the toxins. No matter upon what medium a true 

 toxin producer is grown, the toxin is qualitatively the same, whereas the 

 nature and toxicity of ptomains depend upon the microorganism, the 

 culture-medium used, the duration of growth, and the quantity of oxygen 



