This cap has near its center a "prick-hole" through which the steam continues to escape. This "prick-hole" is then closed with solder, and the closed can again heated in the water bath or with steam. If the can "blows" (if the ends of the can become convex) during this last heating the "prick-hole" is again punctured and the heated air allowed to escape, after which the "prick-hole" is again closed. Cans thus prepared should be allowed to stand in a warm chamber for four or five days. If the contents have not been thoroughly sterilized gases will be evolved during this time, or the can will "blow" and the contents should be discarded. Unscrupulous manufacturers take cans which have "blown," prick them to allow the escape of the contained gases, and then resterilize the cans with their contents, close them again, and put them on the market. These "blowholes" may be made in either end of the can, or they may be made in the sides of the can, where they are subsequently covered with the label. Of course, it does not necessarily follow that if a can has "blown" and been subsequently resterilized its contents will prove poisonous, but it is not safe to eat the contents of such cans. Reputable manufacturers discard all "blown" cans. Nearly all canned jellies sold in this country are made from apples. The apples are boiled with a preparation sold under the trade name "tartarine." This consists of either dilute hydrochloric or sulphuric acid. Samples examined by the writer have invariably been found to consist of dilute hydrochloric acid. The jelly thus formed by the action of the dilute acid upon the apple is converted into quince, pear, pineapple, or any other fruit that the pleasure of the manufacturer may choose by the addition of artificial flavoring agents. There is no reason for believing that the jellies thus prepared are harmful to health. Canned fruits occasionally contain salicylic acid in some form. There has been considerable discussion among sanitarians as to whether or not the use of this preservative is admissible. Serious poisoning with canned fruits is very rare. However, there can be but little doubt that many minor digestive disturbances are caused by acids formed in these foods. There has been much apprehension concerning the possibility of poisoning resulting from the soluble salts of tin formed by the action of fruit acids upon the can. The writer believes that anxiety on this point is unnecessary, and he has failed to find any positive evidence of poisoning resulting from this cause.