BORIC ACID UPON NUTRITION. 39 



lowered, and careful examination of the urine daily with Jaffe's 

 indoxyl test failed to reveal any indications pointing to an 

 inhibitory influence exerted by either borax or boric acid upon 

 the production of indican. If, however, one studies carefully 

 the output of combined sulphuric acid as shown in the various 

 tables it will be noticed that the highest figures are generally 

 obtained on the day (or the day preceding that) on which the 

 dog defecates ; while after defecation the combined sulphuric 

 acid of the urine falls at once. In other words, the natural 

 obstruction of the intestine favors, as is well known, the ab- 

 sorption of putrefactive products, and thus leads to an increase 

 of combined sulphuric acid in the urine. When, on the other 

 hand, defecation occurs, the combined sulphuric acid of the 

 urine is at once diminished in amount. Upon these natural 

 fluctuations of combined sulphuric acid even the largest doses of 

 borax and boric acid are without effect, not because these agents 

 are without influence upon micro-organisms, but because they 

 are too rapidly and completely absorbed from the intestine to 

 exert much influence upon intestinal putrefaction. In only one 

 instance were we able to detect any boric acid in the faeces, viz., 

 on June 5th, at a time when the largest doses of borax were 

 being given ; and at the close of this period the boric acid reac- 

 tion could be obtained with the urine only on the first day of the 

 after period, so rapidly was the borax passed out of the body. 



Lastly, attention may be called to the constant presence, in 

 appreciable amounts, of uric acid in the urine of all the animals 

 experimented with, in opposition to the older statements of 

 Liebig * and others that kynurenic acid may entirely replace 

 uric acid in the urine of the dog. Our results, so far as they 

 extend, are thus wholly in accord with the recent observations 

 of Solomin.f We have, however, made no attempt to deter- 

 mine the amounts of kynurenic acid present. 



General Conclusions. Moderate doses of borax up to 5 

 grams per day, even when continued for some tune, are with- 



* Liebig, Annalen d. Chem. u. Pharm., Band 86, p. 125. 

 t Solomin, Zur Kenntniss der Kynurensaure. Zeitschr. f. physiol. Chem., 

 1897, Band 23, p. 497. 



