PREVENTION OF BOTULISM 217 



rise to substances commonly called ptomains which are 

 poisonous to man if taken in food. At the present time 

 considerable prominence is being given to a kind of food 

 poisoning known as botulism, in which canned food be- 

 comes poisonous through the growth within it of micro- 

 organisms whose waste products are injurious to the 

 human body. 



Prevention of Botulism. — The organisms of botu- 

 lism produce spores (see Chap. XXV) which are very 

 resistant to heat. If any of these spores happen to be 

 present upon spinach or string beans or other vegetables, 

 some of them may escape destruction during the canning 

 process and may therefore be able to develop into active 

 organisms and multiply enormously within the can. Both 

 the active organisms and the poisons which they pro- 

 duce are destroyed at the temperature of boiling water, 

 so that if the food is heated to the boiling point shortly 

 before being eaten it cannot possibly produce botulism 

 poisoning. 



Intestinal Putrefaction. — It has long been known 

 that the intestinal tract in the higher animals harbors 

 many organisms. For the most part these are minute, 

 being either plant forms, bacteria, or one-celled animals, 

 protozoa. Indigestible and undigested constituents of the 

 food afford highly favorable nutritive material for 

 them, so they thrive and multiply. For the most part 

 their presence makes no difference, so far as we know, 

 to the organism which serves as host; but on occasion 

 their growth is accompanied by the production of poison- 

 ous material which can be and often is absorbed from the 

 intestine into the blood, and so is distributed throughout 

 the body. If the intestine fails to be evacuated at suffi- 

 ciently frequent intervals, the production and absorption 

 of these poisons goes on uninterruptedly and constitutes 

 a definite cause of disease. This condition is commonly 

 referred to as auto-intoxication, signifying that the body 

 is poisoning itself. It has received less attention than it 



