URINE. 291 



the average quantity discharged in the course of the day 

 amounts to from ten to seventeen pounds. 



Opinions regarding the composition of the urine are very 

 contradictory, and sufficient analyses have not yet been insti- 

 tuted to enable us to regard any one view as positively correct. 

 Some assert that as the sugar increases in the urine the urea 

 and uric acid decrease, while others maintain that although the 

 absolute quantity of urea in a given amount of urine is actually 

 diminished, yet that on account of the large quantity of urine 

 discharged, the amount of urea is not less than, and in fact 

 exceeds the normal average. 



Thus McGregor shows that the urine of twenty-four hours in 

 one case of diabetes contained 1013 grains of urea; in another 

 case he found 945 grains, in a third 810 grains, and in a fourth 

 512 grains, whereas, according to the same authority, the quan- 

 tity excreted by a healthy person in twenty-four hours does not 

 exceed from 362 to 428 grains. Kane also found in diabetic 

 urine as large a proportion of urea as in the normal secretion. 

 My own analyses certainly tend to show that the ratio of urea 

 to the solid residue is always much less than in health, and 

 that this ratio is diminished in proportion to the increase in the 

 quantity of the sugar ; bearing in mind, however, the increased 

 secretion of urine, it is very possible that in some cases the urea 

 is not absolutely diminished : the apparent connexion between 

 the urea and the sugar may then be simply explained by the 

 mere increase of the sugar, which, by increasing the solid residue, 

 causes a relative diminution of the urea. 1 The same is probably 

 the case with respect to the uric acid ; when no crystals of uric 

 acid are separated after the addition of free hydrochloric or 

 nitric acid to diabetic urine, the cause may lie in the proportion 



1 In connexion with this subject, we may refer to the experiments of Henry. On 

 mixing the residue of six quarts of diabetic urine with the residue of one quart of 

 healthy urine, and adding nitric acid, only a small quantity of nitrate of urea was 

 obtained after the mixture had stood for twenty-four hours ; and on mixing the re- 

 sidue of eight quarts of diabetic urine with that of one quart of healthy urine, and 

 treating it in a similar manner, not a crystal of nitrate of urea could be observed after 

 it had stood for forty-eight hours. Hence it is indispensably requisite that the sugar 

 should be first removed (as completely as possible) before we attempt to determine 

 the urea. 



