1892.] The Influence of the Kidney on Metabolism. 



35 



In the remaining" four dogs described in Table IV the amount of 

 kidney removed was slightly less, and, as the table shows, the results 

 are different to those described in the ten rapidly fatal cases. 



In none of these cases was the operation fatal, and, as previously 

 mentioned, the animals were killed 47 days, 60 days, 14 days, and 

 30 days respectively after the second operation. In no case was there 

 any great emaciation, the greatest loss of weight being in No. 11, 

 where the body weight fell from 14 lbs. to 12 lbs. In all cases there 

 was marked hydruria, but the polyuria was slight or absent, not- 

 withstanding the fact that there was no failure of appetite. Thus 

 these four experiments are in great contrast to the other ten, where 

 a larger amount of kidney w r as removed with a uniformly fatal result. 

 It is clear from these results that the increased flow of urine is not 

 dependent simply upon any increased excretion of urea, since the 

 former may exist without the latter. In no case, however, has an 

 increased excretion of urea been obtained without an increase in the 

 quantity of urine. 



In no case amongst the ten fatal ones (where three-fourths of the 

 total kidney weight was removed) has the operation been followed 

 by a diminution in the output of urea, provided the ingesta were not 

 diminished. 



We may then form the following conclusion, that when a dog is 

 left with only one-fourth of its total kidney weight, a condition of 

 extreme hydruria invariably results. This hydruria is accompanied, 

 provided the appetite does not fail, by a large increase in the output 

 of urea. Further, that if the ingesta are diminished even to zero, 

 the output of urea remains at the height it reached with a diet 

 sufficient to maintain the weight of the animal when in a normal 

 condition. 



That the hydruria, although associated with an increased excretion 

 of urea, is not dependent upon it, is shown not only by the fact men- 

 tioned above, that by removal of a smaller amount of kidney hydruria 

 pure and simple is produced, but also by the fact that when both 

 hydruria and polyuria are produced they do not begin simultaneously. 

 In other words, when hydruria and polyuria are both ultimately pro- 

 duced by removal of three-fourths of the total kidney weight, the 

 hydruria precedes the polyuria. To illustrate this, it will be sufficient 

 to quote one experiment, i.e., No. 23. After the first operation, when 

 6*5 grams of the left kidney were removed, the dog passed 140 c.c. of 

 urine containing 15 grams of urea per diem, with a diet of 150 grams 

 of meat. On increasing the food to 200 grams of meat per diem, 

 the urine rose to 212 c.c, containing 17 grams of urea. The second 

 kidney, weighing 22 grams, was then removed. In the week fol- 

 lowing the operation the ingesta fell to 120 grams, and the urea to 

 13 grams per diem, the urine rising to 380 c.c. In the second week 



D 2 



