If a low proteid diet works so inimically on high proteid animals as Munk and Rosenheim thought, it would naturally be expected that the small proteid ration followed so long by Jägerroos would have resulted in the appearance of marked symptoms, at least a gradual and persistent falling off in body-weight, inability to maintain nitrogen equilibrium, etc.; but none of these things occurred. In Munk’s first experiment, the animal was given no fresh meat whatever during four weeks. Is it not quite possible that in the abrupt cutting off of this wonted form of food a disturbance may have been set up in the gastro-intestinal tract, which paved the way for the more serious results that followed? Jägerroos used only fresh, uncooked meat in his experiments, and laid great stress upon the importance of not departing any more than was necessary from the accustomed form of diet. The writer is strongly of the opinion that sufficient stress has not been laid upon this phase of the subject. A satisfactory diet for dog as for man must meet ordinary hygienic requirements; it must not only be sufficient in amount, but it must be easily digestible, of accustomed flavor, appealing to eye, nostrils, and palate, with reasonable variation occasionally and of moderate volume. With due regard to these conditions, I believe with Jägerroos that not much attention need be paid to the proportion of nitrogen therein, for however small the amount it will be found sufficient to meet the needs of the body. These are the results, collectively, so frequently used to point a moral for man: Beware of the possible danger of reducing the consumption of proteid food below the commonly accepted dietary standards! We must admit, however, that there is a woeful lack of agreement in these results, and it is difficult to prevent a shadow of doubt from creeping over us as we try to depict for ourselves the way in which a low proteid ration exerts its deleterious effect on dogs. I do not believe that radical changes in diet, whether they involve increase or decrease in total quantities, or in specific elements of the diet, can be made suddenly without danger of some disturbance of the gastro-intestinal tract or other parts of the economy, either in dog or man. It is reasonable to believe also that a high proteid feeder, like a dog, with his more limited dietary, will be far more sensitive to great changes than omnivorous man with his wider range of foodstuffs. Moreover, there is just as good ground for believing that in any animal, excess of proteid is as dangerous as a low proteid diet. Too great a disturbance in the nutritive balance, whether it involves excess or reduction in the amount of a given foodstuff, is liable to be attended with serious disturbance in any sensitive organism.