URINE. 249 



it may undergo decomposition there, and by its irritative action 

 on the vesical mucous membrane produce an excessive secretion 

 of mucus or even pus. 



Becquerel found that the density of the urine, except in those 

 cases in which there was great prostration of strength, was above 

 that of normal urine, and amounted on an average to 1023*5. 

 This, as I have already observed, is opposed to my own obser- 

 vations. The mean specific gravity of the urine which threw 

 down a spontaneous sediment was, according to Becquerel, 

 1024-7. The colour of the urine increased with the concentra- 

 tion. The colour of the spontaneous sediments in some cases 

 resembled the brick-dust tint of the sedimentum latericium ; 

 the precipitates thrown down by acids were usually of a yellowish 

 or gray colour. 



In the thirty-eight cases of typhus observed by Becquerel, 

 pus occurred in the urine of only one individual, and in this 

 case the secretion was alkaline; in all the others it was acid. In 

 a very extensive series of observations made by Andral the urine 

 was found to have an acid reaction, except in the following cases, 

 viz. when pus was present, when the urine had remained for a 

 long time in the bladder, when the patient had taken a great 

 quantity of alkaline fluids, or, lastly, when the secretion was 

 not examined for some hours after its discharge. 



The precipitate which Becquerel observed in the urine of 

 typhus, whether thrown down spontaneously or after the addi- 

 tion of an acid, consisted of amorphous or crystalline uric 

 acid ; the latter was only seen twice, once after the addition of 

 a little nitric acid, and in the other instance forming a portion 

 of a spontaneous sediment. These spontaneous deposits were 

 usually of a gray or reddish colour. 



The important questions, whether urinary sediments in typhus 

 occur at any fixed epochs of the disease ? whether there is any 

 connexion between their appearance and a favorable result ? 

 and whether their presence is prognostic of such a result ? are 

 answered by Becquerel in the negative. 



From a table communicated by Becquerel it appears that 

 some persons died in whom the urine deposited a sediment 

 either spontaneously or on the addition of an acid, almost un- 

 interruptedly from the fifth or seventh day ; while others, under 

 similar circumstances, recovered : in a case, in which the 



