Poisoning by plain milk is less common than from certain varieties of cheese and from cream. When ice cream is made in large quantities, the cream is allowed to accumulate, and if a portion of it becomes infected with pathogenic organisms it will soon convert the whole mass into highly poisonous material. In a small town in Indiana, in 1900, over one hundred persons were seriously poisoned by ice cream from soiled cans. Many other such casualties have been observed of late years. Sixty-seven men, at the San Juan garrison in Porto Rico, were poisoned in 1900 by condensed milk. In the U. S. Surgeon-General's report for 1900, the symptoms are described as follows by Assistant Surgeon George M. Wells, U. S. A.:

" The symptoms were persistent vomiting, severe cramps in the stomach, purging, great prostration, dilatation of the pupils, headache, clammy perspiration, chilliness, and great thirst. The stomach in each case was washed out by means of the stomach tube. In some cases the stomach was empty, and nothing but water and mucus came away; in others the washings were tinged with bile, and in others again a moderate amount of food that had been eaten for breakfast was washed out, but in no case was the stomach overdistended or even full. The vomiting was controlled in several instances by the washing out of the stomach, but in many it persisted for several hours afterwards. The prostration was so great that some of the patients fainted before reaching the ward. A large number vomited blood in small clots, in most instances mixed with nothing but mucus, showing that the haemorrhage had not taken place until after the contents of the stomach had been expelled. Purging began in most before the vomiting had ceased, and continued for twelve to fifteen hours. At first the stools were natural, soon watery, afterwards becoming mucous and blood tinged.

Cramps in the voluntary muscles were mild in some, but other patients writhed in agony, their sufferings being relieved only after thorough kneading and massage by the hospital attendants. Forty were discharged from hospital on the following morning; the others from day to day until, the fifth morning, when all were returned to duty".

Vaughan and Novy in this country have thoroughly studied the whole subject of ptomaine poisoning, and Vaughan has isolated from cheese and ice cream a toxin to which he has given the name of "tyrotoxicon," and in Michigan in i883-'84 nearly three hundred instances of cheese poisoning were collected by him. In 1890 he isolated three proteid substances from germ cultures from the intestines of infants having milk infection. The symptoms of tyrotoxicon poisoning are substantially the same with those of meat poisoning, consisting of severe gastro-intestinal disturbance with collapse.

This toxin produces almost immediately after ingestion by a previously healthy infant violent symptoms of cholera morbus, which prove fatal in a few hours unless the poison can be eliminated. (See Cholera Morbus Treatment.) Of this poison Vaughan says: " Post-mortem examination shows but little change. [There is time for but little in fatal cases.] The mucous membrane of the small intestine is bleached and softened, and possibly deprived here and there of its superficial epithelium".

The poison apparently acts somewhat as the toxin of Asiatic cholera, by absorption from the intestinal wall, and by violently deranging the nervous and vascular systems, producing sudden and extreme loss of fluid from the body through osmosis into the intestine.