Buttermilk, so generally regarded as a waste product, has latterly been coming somewhat into vogue, not only as a nutrient, but as a therapeutic agent, and in an editorial article the Canada Lancet, some time ago, highly extolled its virtues. Buttermilk may be roughly described as milk which has lost most of its fat and a small percentage of casein, and which has become sour by fermentation. Long experience has demonstrated it to be an agent of superior digestibility. It is, indeed, a true milk peptone - that is, milk already partly digested, the coagulation of the coagulable portion being loose and flaky, and not of that firm indigestible nature which is the result of the action of the gastric juice upon cow's sweet milk. It resembles koumiss in its nature, and, with the exception of that article, it is the most grateful, refreshing and digestible of the products of milk. It is a decided laxative to the bowels, a fact which must be borne in mind in the treatment of typhoid fever, and which may be turned to advantage in the treatment of habitual constipation. It is a diuretic, and may be prescribed with advantage in some kidney troubles. Owing to its acidity, combined with its laxative properties, it is believed to exercise a general impression on the liver. It is well adapted to many cases where it is customary to recommend lime water and milk. It is invaluable in the treatment of diabetes, either exclusively, or alternating with skimmed milk. In some cases of gastric ulcer and cancer of the stomach, it is the only food that can be retained. Medical journal.