218 EXCRETION. 



Gases of the Urine. 



In the process of separation of the urine from the blood 

 by the kidneys, a certain proportion of the gases in solution 

 in the circulating fluid is also removed. For a long time, 

 indeed, it has been known that the normal human urine con- 

 tained different gases, but lately some very interesting ob- 

 servations on this subject have been made by M. Morin, 1 in 

 which the proportions of the free gases in solution have been 

 accurately estimated. By using the method employed by 

 Magnus in estimating the gases of the blood, 2 Morin was 

 able to extract about two and a half volumes of gas from a 

 hundred parts of urine. By careful experiments, he ascer- 

 tained that a certain quantity of gas remained in the urine, 

 and could not be extracted by his ordinary process. This 

 amounted to about one-fifth of the whole volume of gas. 

 Adding this to the quantity of gas extracted, he obtained 

 the proportions to one litre of urine, in cubic centimetres, 

 which are given in the table, viz. : 



Oxygen 0*824 



Nitrogen 9'589 



Carbonic acid 19*620 



These proportions represent the average of fifteen obser- 

 vations upon the urine secreted during the night. 



The proportion of these gases was found by Morin to be 

 subject to certain variations. For example, after the inges- 

 tion of a considerable quantity of water or any other liquid, 

 the proportion of oxygen was considerably increased (from 

 0*824, to 1*024:), and the carbonic acid was diminished more 



1 MORIN, Recherches sur les gas libres de Vurine. Journal de pharmacie et de 

 chimie, Paris, 1864, tome xlv., p. 396, et seq. 



2 The method of Magnus as applied to the gases of the urine does not in- 

 volve the elements of inaccuracy which we have pointed out with reference to 

 the blood (see vol. i., Respiration, p. 462) ; for in the urine there is no tendency 

 to the disappearance of oxygen and the formation of carbonic acid, such as is 

 due in the blood to the action of the corpuscles. 



