336 



Prof. F. Smith. 



[June .20, 



Here diet undoubtedly influenced its production — as previously pointed 

 out under the head of urea. 



B. Salkowski states that a horse fed on 2 kilos, oats, 2 kilos, hay, 

 and 1 kilo, bran, excreted 65'34 grams of total nitrogen in twenty- 

 four hours. 



According to Tereg and Munk, when horses are fed on rye instead 

 of hay and oats the nitrogen shows no change, but by feeding with 

 peas the nitrogen increases, and that in proportion to the quantity 

 given. If fed on hay alone the excreted nitrogen is very great, a fact 

 as pointed out by these observers, which is very difficult of explana- 

 tion. 



Ammonia. — This exists in the urine of horses free and combined ; 

 the latter has been dealt with and its origin explained, the free 

 ammonia may or may not be due to fermentation occurring in the 

 bladder, bat from a very large number of observations on perfectly 

 healthy horses I affirm that ammonia exists in a free state in fresh 

 urine. 



It may be that ammoniacal fermentation has already taken place 

 in the bladder due to the quantity of mucus, and the long period 

 during which the majority of horses retain their urine, due both to 

 habit and circumstances, but it is quite certain that the perfectly 

 fresh urine caught directly into clean vessels contains a distinct 

 amount of ammonia. The amount of this ammonia cannot be 

 estimated in urine twenty-four hours old, because it is impossible to 

 distinguish if from the ammonia formed as the result of urea de- 

 composition. 



The only way I have attempted to overcome the difficulty is by 

 collecting perfectly fresh urine, and by Schlosing's method determin- 

 ing the ammonia before the slightest urea change, outside the body, 

 has occurred. This process is far from being free from error, but is 

 the least objectionable mode of procedure. 



I have previously stated that the ammonia found in urine twenty- 

 four hours old may safely be calculated as urea, for that is un- 

 doubtedly its origin. 



The preformed ammonia is probably completely given off before 

 the twenty-four hours have ended. The amount of free ammonia in 

 the urine of rest I have calculated at 2'516 grams, and in the urine 

 of work 5*3 grams, but I do not regard these results as completely 

 trustworthy. 



They nevertheless agree very closely, particularly that of work, 

 with the ammonia obtained by the direct titration of fresh urine with 

 a standard acid. 



Phosphoric Acid. — This acid is only found in comparatively small 

 quantities in the urine of horses, the phosphates being principally 

 eliminated by the bowels. 



