with habitual excess in putrefaction. In view of this fact it is clear that in experiments designed to determine the influence of fermented milks upon the intensity of putrefaction it is essential to take accurate cognizance of the quantity of protein ingested. It is easy to understand that if a patient has been in the habit of eating for his midday meal an abundance of protein food and decides under advice to take a fermented milk for his lunch in place of the more elaborate meal, the mere reduction in protein will suffice to reduce putrefaction. So it is clear that a decrease in putrefaction can be effected through a variety of dietaries which have in common the fact that they contain a smaller amount of protein material than the patient has been in the habit of eating. Whole milk and various fermented milks are thus capable of influencing putrefaction in such a way that we may readily fall into the error of exaggerating their influence upon putrefactive decomposition in the intestine. Hence it is evident that the only fair test of the value of a fermented milk in respect to its influence on putrefaction is to compare it with the effects of other articles of diet containing exactly the same amount of protein material. Such careful comparisons have not, I believe, been made up to the present time. In the future they will doubtless be made and will enable us to form quite definite judgments as to the relative effectiveness of different kinds of fermented milks upon intestinal putrefaction. At present I should hesitate to say that one kind of fermented milk is more effective than another in bringing about a reduction in intestinal putrefaction. "We may regard it as well established that a diet in which milk takes the place of other kinds of food is very apt to be followed by a reduction in the intensity of putrefactive decomposition in the intestine. There are, however, clinical indications that the use of fermented milks does possess real advantages over the use of whole milk at least in some disorders of digestion. Although the exact character of these advantages is not yet firmly established, they seem to be none the less real. From what has already been said in this paper on the criteria of judgment of the action of fermented milks, it is evident that the clinical advantages which have been observed may be attributable to several different peculiarities possessed by fermented milks in general. One of these is the favorable mechanical influence on the minute subdivision of the casein, which prevents the undesirable effects associated with the presence of large clots of casein which are not easily disposed of in persons with weak digestion. The exact consequences of this advantageous mechanical state of the milk food can not now be appraised. A second point which has already been mentioned is the formation of lactic acid. Here again the precise extent of the favorable influence can not be measured; but on the other hand it can not be denied that in at least some disorders of digestion the presence
