1880.] 



On the Urine in Disease. 



441 



be made for the nitrogen contained in the pigments and extractives, 

 which are usually not specified, the real percentage would be some- 

 what lower. 



We may, therefore, assume that the urea-nitrogen may be taken as 

 the measure of the total nitrogen, and that this may be approximately 

 determined by adding 10 per cent, to the amount of urea- nitrogen. 



This is, however, only true if the mean of a large number of 

 observations be taken, for there is no fixed relation between, on the 

 one hand, the amount of the urine and the amount of the solids in it, 

 or on the other, between the amount of the various solids inter s$. 

 These all vary independently in great measure of one another, and 

 subject to no law which is at present determined, and stranger still, 

 the relation of the urea-nitrogen to the total nitrogen, even in the same 

 urine on closely consecutive days, is not constant, as the following 

 table shows : — ■ 



I. II. III. 



97- 5 ...... 83-0 87-6 



100-0 95 1 84-2 



91-5 ...... 86-6 87-5 



98- 8 92-4 100-0 



91 -5 87 -9 



82 -3 87 -0 



82-0 



These figures are taken from the tables (Table III) given in the 

 second series of cases, and the variations are not due to altered con- 

 ditions, for the patients were all at absolute rest, and upon a constant 

 diet. If, then, such variations occur when the conditions are constant, 

 they will certainly be not less where the conditions vary.* 



Such variations render it necessary to be specially cautious in draw- 

 ing conclusions from the results of a few experiments, and may explain 

 the great difference in the observations of different investigators. 



Besides the nitrogen, we determined, as we have already stated, the 

 solid residue, the ash, and the chlorine. Of the chlorine, little can be 

 said. Its variations are inexplicable, for although they in part depend 

 upon the amount of chlorine ingested in the food, they seem subject to 

 other influences which we do not at present comprehend. 



The same may be said of the solid residue, and of the ash, and we 

 can do little more than point to the great and irregular variations in 

 the amount of each, which the tables show. 



The result then of our observations is to prove that the chemistry of 

 the urine remains essentially the same in disease as in health, and that 

 the generalisation of Professor Parkes is true in either case. The urea 



* Cf . a similar series of observations by Dr. Byrne Power, " Dubl. Journ. of Med. 

 Sc.," February, 1875. „ 



