LECT. VI. GASEOUS ENDOSMOSE. 129 



Gaseous Endosmose. It is desirable that an extended 

 series of experiments should be carried on, in order to de- 

 termine the laws of this phenomenon, having in view the 

 reciprocal properties of the gases, their density, and the 

 nature of the interposed membranes. Perhaps, a phenome- 

 non analogous to that of endosmose may happen between 

 the gases. Here is an experiment which shows in what 

 \vay the gases act through membranes, and proves that there 

 is a something resembling endosmose in the interchange 

 which takes place. I partially filled the lungs of a recently 

 killed lamb with oxygen gas, having previously carefully 

 extracted, by suction, all the air that it was possible to with- 

 draw. The trachea being closely tied, I introduced the 

 lungs under a bell-glass, filled with carbonic acid, and in- 

 verted under [over ?] water. In a few moments the lungs 

 began to swell up, and became as much distended as the 

 size of the receiver would admit them to do, I analyzed 

 the gas after the experiment, and found that the carbonic 

 acid had penetrated into the pulmonary cells, and that the 

 oxygen had been disengaged therefrom. The interchange, 

 nevertheless, had not been in equal volumes ; the quantity 

 of carbonic acid which had been introduced into the lungs, 

 being much greater than that of the oxygen which had 

 escaped. In a lung prepared in the way I have just men- 

 tioned, I found that in four hours, the gas contained in it 

 was composed off oxygen, and J carbonic acid, while that 

 in the receiver was \ oxygen, and f carbonic acid. 



Soap bubbles, filled with atmospheric air, or hydrogen, 

 falling into carbonic acid, demonstrated toMarianini a phe- 

 nomenon resembling that which has been observed with the 

 lungs. The bubbles augment in size ; and it is curious that, 

 when thus dilated, they fall to the bottom of the vessel con- 

 taining the acid. The excess of carbonic acid, which has 

 penetrated the bubble, is the cause of the augmented 

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