=Alimentary Intoxications.=--What we have already stated permits us to understand the phenomena of indigestion and botulism. The toxic substances form within the digestive tract when the nervous conditions modify the composition of the gastric juice, and arrest the flow of hydrochloric acid, the presence of which normally checks the development of the microbial flora, so rich within the stomach. The result is the production, within the organism, of all kinds of dangerous toxins. The same thing happens when the liver does not functionate normally, and this, affords us a knowledge of the mechanism by which foods that are most wholesome may become toxic by reason of poor digestion or poor assimilation. The absorption of spoiled viands may, _a fortiori_, produce serious results. The alteration may be due not only to a bacterial infection, as in tainted meat, but it has also been proved that the flesh of an animal that has died of terror or madness may be very dangerous as a food, even after cooking, because, although there are toxins which are destroyed by a sufficient heat, there are ptomaines and certain toxins that resist destruction under these conditions.[74] [74] POLLIN and LABIT: _Examens des aliments suspects_, Masson, publisher. The use of preserved but spoiled beef, preserved ham or birds, sausages frequently, and pieces of pork tainted by sausage poison, gives rise to a succession of toxic symptoms the principal ones of which are dryness, constriction of the pharynx, bilious vomiting, diarrhea, dyspnea with pulmonary edema, etc. Fish and eggs are foods quite frequently capable of developing serious results; the same is the case with molluscs, mussels, oysters, lobsters, and snails. Lastly, moldy bread, spoiled cheese, putrid water, and spoiled vegetables themselves, are proper agents for determining attacks of botulic poisoning. We have seen, at the beginning of this volume, that putrid meats contain ptomaines, which are among the most toxic alkaloidal bases. We have shown that Brieger has isolated from them neuridine, putrescine, muscarine, and guanidine; that Nencki has isolated hydrocollidine; and that Gautier and Etard have obtained from them parvoline--only to mention a few of them. Lastly, there may develop within the gastrointestinal tract dangerous putrefactions, the products of which may enter the veins and arteries from the ileum (a portion of the small intestine) and be distributed throughout the organism. Although such poisonings occur, they do not immediately follow the ingestion of the spoiled or toxic foods, but they are always preceded by a period of incubation varying from several hours to several days.