MICROBIAL FOOD POISONING. 417 



There are also certain definite, more or less chronic diseases which 

 have been attributed to the use of certain grains as foods. Ergotism, 

 characterized by cachexia, gangrene, and convulsions, is caused by eating 

 the fungus, Claviceps purpurea, which grows as a parasite upon rye. The 

 grain of this parasite has a considerable commercial (medicinal) value suffi- 

 cient to pay for its separation from rye where it occurs, so there is little 

 economic excuse for food poisoning from this cause. Beriberi or kakke 

 is a chronic nervous disorder which occurs especially among the Japanese, 

 at one time ascribed to the use of fish and later to the use of rice as food. 

 The rice hypothesis has considerable observational and experimental 

 evidence to support it, but can hardly be regarded as definitely established. 

 Pellagera is a cachexia, characterized by a definite sort of skin eruption, 

 which has been ascribed to the use of maize (Indian corn) as food. This 

 disease is discussed in a separate section. 



THE CHEMICAL NATURE or FOOD POISONS. 



The poisonous substances in foods are for the most part of the same 

 nature as the poisons of the pathogenic bacteria. The simplest in structure 

 of these poisons belong to the alkaloidal substances, substituted ammonia 

 and ammonium compounds, called ptoma'ins (p. 115). Several of these 

 have been prepared in a pure state, for example, mytilotoxin (C 6 H 15 NO 2 ) 

 from poisonous shell-fish, and neurin (C 2 H 3 -N(CH 3 ) 3 'OH) from putre- 

 fied horse, beef, and human flesh. Although ptomai'ns undoubtedly occur 

 at times in poisonous foods, they are not now considered of so much im- 

 portance in food poisoning as formerly, for in the majority of samples of 

 poisonous food the search for ptomams has been in vain. The poisonous 

 effects are believed rather to be due for the most part to much more com- 

 plex bodies resulting from the earliest analytic changes in the food 

 protein, or else to bodies built up by actual synthesis by the bacteria. 

 Such substances are classed with the toxic proteins and the true toxins. 

 Their chemical composition and structure are not definitely known. 



REFERENCES. 



Dieudonne, A., translation by Bolduan, C. F., Bacterial food poisoning. E. B. 

 Treat and Co., New York, 1909. 



Nervy, F. G., Food poisons, Osier's Modern Medicine, Vol. I. Lea Bros., and Co., 

 Philadelphia, 1907. 



Thresh and Porter, Preservatives in food and food examination. J. and A. 

 Churchill, London, 1906. 



Vaughan and Novy, Cellular toxins. Lea Bros., and Co., Philadelphia, 1902. 

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