1YG DISEASES OF THE PARENCHYMA OF THE LUXG. 



of urea and uric acid. The elevation of the temperature of the bod y 

 in febrile disease depends upon an abnormal generation of heat from a 

 morbidly-active combustion of the constituents of the tissues, in which, 

 of course, the nitrogenous elements participate. A short fever reduces 

 the weight of the patient far more than does a fast, without fever, of 

 much longer duration. But the patient not only grows thin because 

 his fat is consumed in overheating his body, but the muscles undergo a 

 marked atrophy, and a considerable period of time elapses ere a con- 

 valescent from fever regains his former strength, and ere his muscles are 

 restored to their original volume. The increased destructive assimila- 

 tion of the nitrogenous constituents of the body during fever is also 

 susceptible of direct proof, by the absolute or relative augmentation in 

 the production of urea. Patients suffering from pneumonia, with violent 

 fever, even though their diet be absolutely non-nitrogenous, eliminate 

 quite as much urea in their urine, if not more, than a healthy person 

 does whose food consists almost entirely of meat and eggs. I have 

 known pneumonia patients to excrete forty grammes of urea within 

 twenty-four hours, while one of my pupils, who was in good health, 

 and whose diet was precisely that of the sick man, passed but from 

 thirteen to fifteen grammes in the same time. The urine very com- 

 monly becomes turbid upon cooling, from precipitation of its urates ; 

 but it appears to me that this phenomenon is due rather to the reduced 

 proportion of water in the urine, which thus becomes incapable of hold- 

 ing the urates in solution at a low temperature, than to an excessive 

 formation of the salts themselves. By gently warming the urine the 

 urates can always be redissolyed, and the cloudiness of the urine be 

 dissipated. 



While the urea of the urine is increased hi quantity, the amount of 

 inorganic salts which it contains, especially its alkaline chlorides, is 

 diminished, and at the height of the disease they may disappear com- 

 pletely. If we add a few drops of a solution of nitrate of silver to 

 some of the urine, previously acidulated, the precipitate of chloride of 

 silver, so distinct in healthy urine, is scarcely, if at all, observable. 

 The greater part of this chloride of sodium depends, no doubt, upon 

 the use of food containing salt, and the diet of a pneumonia patient 

 might account for the diminution of alkaline chlorides in the secretion ; 

 but as, even in starving animals, small quantities of alkaline chlorides 

 are found in the urine, as a product of transmutation of their tissues, 

 its complete disappearance in pneumonia cannot be attributed solely to 

 the diet of the patient : and we are warranted in supposing that the 

 portion of alkaline chlorides produced by destructive assimilation is ex- 

 creted from the blood with the pneumonic exudation. 



The concentration of the urine, the augmentation of urea, the dimr 



