BORIC ACID UPON NUTRITION. 37 



proteolytic action of both digestive fluids. Further, retarda- 

 tion of proteolysis with borax is much more pronounced than 

 with boric acid ; hence it seems quite probable that the 

 increased bulk of faeces and the higher content of nitrogen 

 therein during the borax periods is due mainly to slight 

 retardation in the assimilation of proteid food. 



Large amounts of borax likewise interfere with the assimi- 

 lation of fatty foods ; a statement which does not appear to 

 be true of boric acid. In the accompanying table (page 38) 

 are given the results of our analyses of the dry faeces, from 

 a study of which it is plain that under the influence of large 

 doses of borax first and second borax periods of experiment 

 third both the total and percentage amounts of ether-soluble 

 matter in the faeces are greatly increased. Boric acid, on the 

 other hand, produces no such effect. In the first experiment, 

 with borax, the evidence of decreased fat absorption is less 

 pronounced, although both the dosage of borax and the 

 amount of fat fed were greater than in the first borax period 

 of experiment third. Quite possibly this apparent difference 

 in action may be due to the personality of the animal. How- 

 ever this may be, it is plain that large doses of borax are 

 prone to increase somewhat the bulk of the faeces, in part 

 by diminishing slightly the assimilation of both proteid and 

 fatty food, and in part, we think, through a tendency to 

 increase the secretion of mucus. Thus, we observed in the 

 last experiment, during the period when the largest doses of 

 borax were given, that the faeces were more slimy than in the 

 normal periods, and appeared to contain more mucus than 

 ordinarily. Further, it is to be noted that under the influence 

 of large doses of borax there is a tendency toward diarrhoea ; 

 not very marked to be sure, but sufficient to render the 

 discharge of faeces somewhat watery. 



In spite of these evidences of minor action in the intestinal 

 tract with large doses of borax, there is no evidence whatever 

 of any influence exerted upon intestinal putrefaction, either by 

 borax or boric acid. Even with the largest doses of borax the 

 combined sulphuric acid of the urine is raised rather than 



