12 THE COMPOSITION OF EXPIRED AIK, 



with potash solution to absorb the caibonic acid ; 3200 expirations of aii- were 

 conducted into the glass vessel during the three hours — no effect noticeable. In a 

 second experiment the carbonic acid was not absorbed, the experiment histing four 

 houi-s — no effect. 



He repeated the " BrownSuquard " experiment, using white mice in four glass 

 cages. The death of the animals, he believes, was due to changes in the tempera- 

 ture and the accumulation of moisture in the jai's. He believes the protection 

 afforded by HgSO^ in BrownSequard and d'Arsouval's experiments was due to its 

 abstraction of the moisture from the air. An acute poisoning through the organic 

 matters contained in the expired air he believes to be impossible, or at least as 

 not shown by anything in his experiments. 



Rauer, in 1893, (32), used white mice confined in glass vessels of about 1^ 

 litres capacity, the bottom of which was covered with oats. The cork was per- 

 forated by three tubes: one of these passed down near the bottom of the vessel 

 and served for the enti'ance of the air ; the second terminated just below the coi-k 

 and served for the exit of air ; and the third extended down to about the height 

 of the animal but was usually closed, this was only used for the removal of air for 

 its chemical examination. In the beginning, thermometers and hygrometers were 

 used in the vessels, but they were found to be unimportant and were abandoned. 

 The whole apparatus was connected with a large aspirator. 



In an experiment with five animals and a ventilation of four litres per hour, 

 the carbonic acid was found to amount to 9.3 percent, after five hours. In another 

 experiment with six animals and with a ventilation of 2^ litres per houi-, he inserted 

 four absorption tubes with soda-lime between the last two jai's, and a Geissler tube 

 containing concentrated HgSO^ between the fourth and fifth. The sixth animal 

 remained alive while the fifth died earlier than the fifth animal in the first experi- 

 ment. He concludes that there is no organic poison in expired air, death being 

 due to the excess of carbonic acid in the atmospheres of the jars. 



Sanfelice, in 1893, (33), reported that he had repeated the " Hammond " 

 experiment, using a flask of about 5 liti'es capacity, the animal dying in six or 

 seven hoTlrs. He is undecided as to the existence of a volatile expiratoiy poison, 

 though he thinks that other factors, for instance, heat radiation, have an important 

 influence upon the results. 



Liibbert and Peters, in 1894, (34), reported that they had repeated the "Brown- 

 Sequard " expei'iment, placing a guinea-pig in each of a series of four flasks. 

 Between the third and fourtli flasks they placed a combustion tube through which 

 the air coming from the third flask was conducted, passing over red-hot cupric 

 oxide, to remove the organic matter. Before reaching the fourth flask, the air was 



