FORMATION -OF THE URIXE. 167 



and is replaced by the ammoniacal salts. 1 Consequently, 

 after removal of the kidneys, we should not expect to find 

 an increased quantity of urea in the blood, until its elimina- 

 tion by the mucous membrane of the alimentary canal has 

 ceased ; but the fact that it then accumulates in large quan- 

 tity cannot be doubted. 



The results of the experiments of Dr. Hammond entirely 

 correspond with those obtained by Bernard and Barreswill. 

 He has also confirmed the fact, observed by Segalas and 

 Yauquelin, that urea is an active diuretic when injected in 

 small quantity into the veins of a healthy animal ; 3 and that 

 in this case it does not produce any poisonous effects, but is 

 immediately eliminated. But when urea is injected into 

 the vascular system of a nephrotomized animal, it produces 

 death in a very short time, with the characteristic symptoms 

 of uraemic poisoning. 3 We have frequently removed both 

 kidneys from dogs, and when the operation is carefully per- 

 formed, the animals live for from three to five days. In some 

 instances they have been known to live for twelve days or 

 even longer, 4 but death always takes place finally with 

 symptoms of blood-poisoning. 



The experiments which are supposed to show that urea 

 and the urates are actually formed in the kidneys to which 

 we have already alluded were made with the view of com- 

 paring the effects of removal of both kidneys with those 

 produced by tying the ureters. According to the observa- 

 tions of Oppler, the blood contains much more urea after 

 the ureters are tied than after removal of the kidneys. 6 Perls 

 states, as the result of experiments on rabbits, that no accu- 

 mulation of urea in the muscular substance can be proved 



1 BERNARD, op. cit., p. 51. 



2 SEGALAS, loc. cit. 



3 HAMMOND, Physiological Memoirs Urcemic Intoxication, Philadelphia, 

 1863, p. 347. 



4 HAMMOND, op. cit., p. 303. 



5 OPPLER, Beitrdge zur Lehre von der Uramie. VIRCHOW'S Archiv, Berlin, 

 1861, Bd. xxi., S. 260, et aeq. 



