1889.] The Chemistry of the Urine of the Horse. 



331 



off in twenty-four hours. Calculated as ammonia, the mean volatile 

 alkalinity in twenty-four hours old urine amounts to 7*1016 grams for 

 work and 7*8534 for rest ; these amounts I have added on to the urea, 

 as I am convinced from long observation that they are formed from 

 this substance. The fixed alkalinity expressed in terms of KHO 

 gives a mean of 2*954 grams in urine twenty- four hours old, but in 

 perfectly fresh urine it is equivalent to 4*8856 grams of KHO in 

 twenty-four hours ; this latter is probably too high. 



Consistence. — A large quantity of mucus in the urine is by no 

 means an uncommon condition ; this is particularly the case in mares, 

 the urine being so thick and tenacious (more like linseed oil in con- 

 sistence) that it takes some hours to get sufficient through the filter 

 for analysis. 



The smaller the bulk of fluid excreted, the larger the amount of 

 mucus it contains ; it then becomes sticky and difficult to work with, 

 still, it is a perfectly natural condition. In a urine of average con- 

 sistence I have found 21*9 grams of mucus, and in one very tenacious 

 31*396 grams in twenty-four hours. 



Specific Gravity. — The mean specific density is 1036, the highest 

 registered was 1050 and the lowest 1014. The formulas of Trapp and 

 Christison will not apply to the urine of the horse. Solids calculated 

 by these give untrustworthy results. 



Quantity of Urine. — The mean amount of fluid excreted by working 

 horses is 4474 c.c. and in animals that rest 4935 c.c. The largest 

 amount produced in twenty-four hours was 11,300 c.c, and the 

 smallest quantity secreted 2000 c.c. Neither season, sex, or age pro- 

 duced any effect on the quantity of fluid secreted. In thirteen 

 observations on the same horse, embracing both hot and cold weather, 

 the largest quantities passed, amounting to over 10 litres, were 

 produced during warm summer months. I place, however, no stress 

 on this observation ; probably in another series of experiments the 

 results would be reversed. 



It is obvious that much of the bulk of fluid secreted will depend 

 upon the quantity consumed. It is notorious that working horses 

 are often stinted in their water. In one very careful experiment, 

 where all the water was measured, it was found that more urine was 

 excreted during the twenty-four hours subsequent to work than was 

 excreted after absolute rest for one week. The water of the twenty- 

 four hours' urine equals \ to \ of the water drunk. 



Chemical Characters of the Urine. 



Total Solids. — The mean amount of solids excreted by horses at 

 rest was 230*0713 grams; of these the combustible solids are repre- 

 sented by 146*1649 and the ash by 83*9064 grams. The total solids of 



