86 



Scientific Proceedings (90). 



renal test day contributed little of value. Nocturnal polyuria 

 was constant but quite independent of the kidneys' ability to 

 concentrate. "Maximal impairment," according to Mosenthal, 

 occurred in two cases, one showing no other abnormalities of 

 renal function, and the other with very moderate impairment, 

 while a fatal case concentrated to 1.022. The balances of salt 

 and nitrogen so frequently included in the performance of this test 

 were not done because of the obvious unreliability of a twenty- 

 four-hour experiment. Moreover, in view of its great dependence 

 upon a factor so variable as the amount of water excreted, sys- 

 tematic determinations of the specific gravity over a brief period 

 must be very carefully interpreted. Many inconsistent phthalein 

 results were found, but in general the value of the test in acute 

 nephritis may be summed up by saying that variations above a 

 level of 20 to 25 per cent, were rarely of a functional signifi- 

 cance coinciding with the rest of the picture. A figure below 20 

 per cent, was -of more serious import, although one case excreting 

 only 15 per cent, recovered completely. 



The blood urea estimations proved the most consistently 

 valuable means of determining the severity of the disease in any 

 given case. The highest figure was in the only fatal case, the other 

 high figure was undoubtedly the next most severe, while the two 

 cases without any evidence of retention made the most rapid 

 recoveries. 



If we overlook variations above the normal and consider the 

 usual rather than the average results, we have in the urea index 

 an expression of the gross renal function that agrees fairly well 

 with the impression gleaned from the other data. But I would 

 hasten to add that even moderately rigid interpretation of the 

 Ambard as a real index of urea function may lead to the greatest 

 error. This criticism is based on such observations as the follow- 

 ing. At constant levels of blood urea, an increase in the water 

 excretion in one case caused a 28 per cent, drop in the index 

 (according to McLean's formula), although the rate of excretion 

 (D.) was the same. 



Date. 



Volume Urine. 



Blood Urea. 



Rate — D. 



Index. 



Feb. 28 



1,128 



O.38 



22.5 



98 



Mar. 14 



2,448 



0-37 



22.4 



70 



