132 THE FEEDING OF ANIMALS 



fed the activity of the cellulose digesting bacteria is 

 diverted from the crude fiber to the more readily avail- 

 able starches or sugars. A modifying conclusion is, that 

 if the addition of the carbohydrate material is accom- 

 panied by correspondingly more protein, the depression 

 of the digestion coefficients is much lessened or does not 

 occur. Many data are cited in support of these generali- 

 zations which are worthy of careful consideration. 



It is not unreasonable to suppose that the relative 

 quantity in a ration of the several classes of nutrients 

 may have an influence upon the digestive processes, and 

 we should accept the verdict of previous observations in 

 so far as they will bear critical discussion and further 

 investigation. But it should be said, by way of comment, 

 that the carbohydrate material in the experiments cited 

 has usually been fed in addition to a basal ration, thus 

 increasing the amount of food consumed, and, as we have 

 seen, this may have an influence upon the proportion of 

 total dry matter digested. In this particular, the experi- 

 ments have not been logical. Again, in these experi- 

 ments, no allowance has been made for the metabolic 

 wastes in the feces, i. e., that material not belonging to 

 the true undigested residue. As this appears to be inde- 

 pendent of the amount of protein fed and stands more 

 nearly in relation to the total digested nutrients, it fol- 

 lows that the smaller the proportion of protein in the 

 digested food, the larger the error caused in the coeffi- 

 cient for protein by the waste nitrogen products. A careful 

 study of this point in the light of more recent knowl- 

 edge might modify the conclusion reached as to the 

 depression of protein digestion through feeding starch 

 or -starchy foods. In all or nearly all the experiments 

 where this effect is apparently shown, the digestible dry 



