1892.] 



The Influence of the Kidney on Metabolism. 



37 



has varied between 95 and 100 mm. Hg, the animal being under the 

 influence of chloroform, that is to say, the blood pressure was as high 

 as it frequently is in normal and healthy chloroformed dogs. This 

 height of the blood pressure is in great contrast to the blood pressure 

 iu dogs after double nephrectomy, where even on the third day the 

 blood pressure has sunk to a few millimetres of mercury. 



Hence the arterial tension is raised when the animal has but ^rd 

 to ^th of its total kidney weight. 



Post-mortem Examination. — The animals are greatly emaciated, but 

 usually some fat remains, especially the omental fat. No marked 

 naked-eye changes have been detected, except a marked excess of 

 cerebro-spinal fluid in the cranial cavity. No obvious change was 

 found in the heart or vessels. The abdominal viscera have been 

 found rather soft and sticky, but no other evidence of septic 

 poisoning or of auto-infection has been found. 



The kidney fragment has never been found hypertrophied ; more 

 frequently distinctly atrophied, the weight of the fragment found 

 post mortem plus the weight of the piece removed being generally 

 less than the weight of the opposite kidney. This is in opposition to 

 the results of a French observer.* He, however, removed at the first 

 operation the entire kidney, and then subsequently removed pieces of 

 the second kidney, which had, as is well known, undergone a so-called 

 compensatory hypertrophy. Under these circumstances Tufner states 

 that the fragment hypertrophies considerably. 



Whether the atrophy observed by me is dependent upon the 

 part of the kidney removed, I trust to elucidate by further observa- 

 tions now in progress. 



Nitrogenous Extractives of the Blood and Tissues. — The animals, 

 after being anaesthetised with chloroform, were bled to death. 50 c.c. 

 of blood were placed in an excess of rectified alcohol and 50 grams of 

 muscle, liver, brain were similarly treated after being finely divided. 

 After prolonged extraction, the filtrate is then evaporated to dryness 

 over a water-bath, and the dry residue repeatedly extracted with cold 

 absolute alcohol, usually for some hours. The absolute extract is 

 evaporated to dryness on the water-bath and the residue dissolved in 

 water. The material insoluble in absolute is also dissolved in water, 

 and thus two watery extracts are obtained which may, for simplicity, 

 be called the absolute and rectified extract; these are treated as 

 follows : — half of each is introduced separately into a Dupre urea 

 apparatus, and the amount of nitrogen evolved by decomposition 

 with sodium hypobromite determined. In the remaining half of each 

 extract the total nitrogen present was determined by Kjeldahl's 

 method. In this manner a control is kept on the hypobromite 

 method, since, if such a body as urea is present, the Dupre and 

 * Tuffier, ' Etudes experimentales sur la Chirurgie du Rein,' Paris, 18S9. 



