52 PATHOGENIC BACTERIA. 



ilar to the preceding, except that instead of occurring in 

 carbohydrates it takes place in nitrogenous bodies. The 

 first step seems to be the transformation of the albumins 

 into peptones, then the splitting up of the peptones into 

 gases, acids, bases, and salts. In the process the innocu- 

 ous albumins are frequently changed to toxalbumins, and 

 sometimes to distinct animal alkaloids known as pto- 

 maines. Vaughan and Novy declare the term "animal 

 alkaloid" to be a misnomer, as ptomaines are sometimes 

 produced from vegetable substances in the process of 

 decomposition; they suggest the term "putrefactive al- 

 kaloids" as preferable. Their definition of a ptomaine 

 is "a chemical compound, basic in character, formed by 

 the action of bacteria on organic matter." The chemis- 

 try of these bodies is very complex, and for a satisfactory 

 description of them Vaughan and Novy's book 1 is excel- 

 lent. Ptomaines probably play but a small part in patho- 

 logical conditions. They are formed almost exclusively 

 outside of the body, and only become a source of danger 

 when ingested with the food. It is supposed that the 

 cases of ice-cream and cheese-poisoning that sometimes 

 occur are due to tyrotoxicon, a ptomaine produced by the 

 putrefaction of the proteid substances of the milk before 

 it is frozen into ice cream or made into cheese. The safe- 

 guard is to freeze the milk only when perfectly fresh and 

 avoid adding the sugar and flavoring substances, and al- 

 lowing the whole to stand some time before it is frozen. 

 Numerous others have been described, some toxic, some 

 harmless. 



It is to compounds of this kind that the occasional 

 cases of " Fleischvergiftung," "meat-poisoning," or 

 " Botulismus," are due, the growth of various bacteria 

 in stale meat bringing about in its proteid substances the 

 development of toxic ptomaines. Kaensche 2 carefully 

 investigated the subject, and gives a synoptical table 

 containing all the described bacteria of this class. His 



1 Ptomaines and Leucomatnes. 



2 Zeitschrift fur Hygiene, etc., Bd. xxii., Heft I, June 25, 1896. 



