"338 



Prof. F. Smith. 



[June 20, 



Lime. — More lime exists in the urine of the horse than is soluble 

 in an alkaline fluid, we have therefore lime bobh dissolved and 

 merely suspended ; these have been estimated separately. No direct 

 connexion could be traced between the lime in the urine and the lime 

 in the food, but between the production of lime and work a direct 

 connexion appeared. The mean amount of dissolved CaO at work 

 was found to be 1*9027 grams, and of the same salt at rest 3 4367 

 grams in twenty-four hours. 



Suspended Lime. — More suspended lime was found in the uirne of 

 horses at work than in those at rest, for the former 3*69 grams, and 

 for the latter 1T043 grams CaO. To state these points briefly, when 

 horses work they excrete more lime in their urine than when at rest, 

 but the lime of work is principally suspended, and only a part of it 

 dissolved ; whereas, the lime of rest is nearly all dissolved, and but 

 little of it suspended. There is no connexion between the amount 

 of mucus in the urine and the suspended lime. 



The largest amount of dissolved lime I found was 16*45 grams and 

 the smallest 0*627 gram in twenty-four hours. The lime is found 

 principally in conjunction with a carbonate, but I have also found 

 sulphate and oxalate. The most common deposit in horse's urine is 

 the wheel-shaped crystals of lime carbonate. 



On adding an acid to urine, extreme effervescence occurs as a rule, 

 and the fluid is left quite clear like human urine ; I have only on a few 

 occasions witnessed any different results from these. The effervescence 

 is usually extreme. 



Magnesia. — This, like the lime, exists partly in the suspended state 

 and partly dissolved. Neither diet nor work have any influence over 

 the production of magnesia. The soluble magnesia of work is 

 2*63 grams, and of rest 2*975 grams. The suspended magnesia of 

 rest is 0*4218 gram, and of work 0*7925 gram. 



Potassium. — This metal is found largely in horse's urine ; it is 

 principally combined with chlorine. 



Rest and work influence its production, there is more potash found 

 in the urine of resting than in the urine of working horses. Working 

 horses gave 27*06 grams whilst resting horses gave 36*59 grams in 

 twenty-four hours. 



Sodium. — Is only found in small quantities in the urine, the mean 

 amount being 2*17 grams, and it is combined with chlorine, yielding a 

 little over 5^ grams of common salt for the twenty-four hours. The 

 mean amount of sodium in working horses was 1*84 grams in twenty- 

 four hours, in horses at rest it was larger, viz., 2*5 grams; yielding 

 with chlorine less than 6-J- grams of common salt per diem. 



In some recent experiments, carried out on a pony, on the excretion 

 of soda and potash during rest and work, the anirnal remaining under 

 observation for several days, I found that the mean amount of 



