The importance of milk as an exclusive article of diet, as an addition to ordinary aliments, and as a constituent of various foods, is so great that some reference must be made to the accidents caused by it under certain circumstances. It has long been observed that milk and cream during the hot season, and sometimes cheese at all seasons, brought on extreme gastric disturbance accompanied by profound prostration. The cause of this change in a fluid so innocuous under other circumstances remained unknown until Prof. C. Vaughan, M. D., of the University of Michigan, made the important discovery. He first isolated a ptomaine in poisonous cheese. Subsequently his technical skill was invoked to determine the cause of wholesale poisoning from ice-cream, when he was able to confirm his former research by the discovery of the toxic principle, to which he gave the name tyrotoxicon. This is a crystalli zable principle formed during the course of the butyric fermentation by the action of the microbe of this process. It is a powerful irritant poison, is acrid in taste, and causes a sense of constriction and a persistent after-acridity in the fauces; sets up an intense gastro-intestinal disturbance, nausea, vomiting, and purging, followed by profound depression of the powers of life. Milk has its disadvantages. Large draughts of cold milk at meals form a heavy curd that may try the stomach severely. There is reason to believe, also, that milk is hurtful to the rheumatic and gouty. As lactic acid results from the fermentation of milk-sugar, or lactose, one of the results of the use of milk may be rheumatic fever—for it is pretty generally held that a variety of lactic acid is the real cause of this disease.