CHAPTEE XI. 



POISONOUS PRODUCTS OF BACTERIA. 



. ALT, the symptoms manifested as a result of the presence 

 of bacteria in the body are due to the elaboration by these 

 bacteria of substances, the chemical composition of which 

 resembles that of the vegetable alkaloids. Some of these 

 substances are formed by bacteria outside of the body and are 

 ingested with food, as poisoning by decomposed meat, fish, 

 cheese, or ice cream. In most cases, however, the poison is 

 elaborated by the bacteria after they have gained entrance 

 into the body, as in the infectious fevers. The severity of the 

 reaction depends upon the kind and the quantity of poison 

 elaborated. 



Ptomaines : A ptomaine is an organic chemical compound, 

 basic in character, formed by the action of bacteria on nitro- 

 genous matter (Vaughan and Novy). A ptomaine is crys- 

 tal lizable. It may be either inert or very poisonous. Brieger 

 calls the non-poisonous substances ptomaines, and the poison- 

 ous ones, toxins. When a ptomaine is injected into an 

 animal in large quantity or for a long period of time, symp- 

 toms of intoxication are produced. Some ptomaines contain 

 oxygen and some do not. They all contain nitrogen. 

 Ptomaines are typical vegetable alkaloids. 



Ptomaines have also been called cadaveric alkaloids, because 

 they are the result of putrefaction. The kind of ptomaine 

 produced depends largely on the individual germ, the tem- 

 perature, amount of oxygen present, virulence or activity of 

 the germ, and the quality of the nutritive medium. Ptomaines 

 are regarded as cleavage-products, temporary forms of matter, 

 as they are changed from an organic to an inorganic state by 

 the action of the bacteria. Although ptomaines may be 

 formed by pathogenic bacteria, they are usually the result of 

 the activity of the non-pathogenic saprophytes. 



