Putrefaction 49 



chemist, depends upon the activity of a yeast-plant, one 

 of the saccharomyces fungi. A number of different bacilli 

 seem capable of converting milk-sugar into lactic acid. 

 There is, therefore, no specific micro-organism for this fer- 

 mentation, though Bacillus acidi lactici is the best known 

 and most active acid producer. There are also several bac- 

 teria which produce the acetic fermentation, though it is 

 generally attributed to Bacillus aceticus. The butyric fer- 

 mentation generally due to Bacillus butyricus may also 

 be caused by other bacilli. (For an exact description of 

 the chemistry of the fermentations reference must be made 

 to special text-books.*) 



Putrefaction Putrefaction is a chemic disintegration 

 of nitrogenous compounds resulting from the activity of 

 micro-organisms. The first step in the process seems to 

 be the transformation of the albumins into peptones, then 

 the splitting up of the peptones into gases, acids, bases, 

 and salts. Both fermentative and putrefactive processes 

 apparently take place through the agency of enzymes 

 produced by the bacteria. In the process the innocuous 

 albumins are frequently changed to toxalbumins, and some- 

 times to peculiar putrefactive alkaloids known as ptomains. 



Ptomains. Vaughan and Novy define a ptomain as "a 

 chemical compound, basic in character, formed by the action 

 of bacteria on organic matter." The chemistry of these 

 bodies is very complex, and for a satisfactory description 

 of them Vaughan and Novy's book f is excellent. 



Ptomains probably play but a small part in pathologic 

 conditions. They are formed almost exclusively outside of 

 the living body, and only become a source of danger when 

 ingested with the food. It is supposed that cases of ice- 

 cream and cheese- poisoning are usually due to tyrotoxicon, 

 a ptomain produced by the putrefaction of the proteid sub- 

 stances of the milk before it is frozen into ice-cream or 

 made into cheese. The safeguard is to freeze the milk only 

 when perfectly fresh and avoid mixing the milk, cream, 

 sugar, and flavoring substances, and allowing the mixture 

 to stand for some time beforehand. 



* See "Enzymes and Their Applications," by Jean Effront, trans- 

 lated by S. C. Prescott, New York, 1902; "Micro-organisms and Fer- 

 mentation," by Alfred Jorgensen, translated by A. K. Miller and 

 A. E. Lennholm, London, 1900; and the many writings of Christian 

 Hansen. 



f " Ptomai'nes and Leucomames," 1888; "Cellular Toxins," 1902. 

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