34 



EFFECTS OF CARBONIC 



OXIDE 



GAS. 



blooded animals, because their muscular and nervous systems, are far more inde- 

 pendent of the circulatory fluid, and the metamorphoses of the organic and inorganic 

 elements of their fluids and solids are far less rapid. 



Carbonic Oxide Gas. 



A Corn Snake [Coluber guttatus) was placed in a jar of carbonic oxide gas. At 

 first, its efforts to escape were unceasing and violent. Gradually, its respiration 

 became more laborious; it gasped violently for breath; its motions became more 

 spasmodic, and were succeeded by intervals of apparent exhaustion. It died in 

 forty-five minutes after its introduction into the gas. 



A Bullfrog [Eana pipiens) placed in the carbonic oxide gas presented similar 

 phenomena, but died in a much shorter time, about ten minutes. This difference 

 of time was without doubt due to the difference in the structure of the tegumentary 

 systems of the two Reptiles; the naked skin of the Frog absorbing the gas much 

 more rapidly than the scaly integument of the Serpent. 



In both animals (examined immediately after their death), the contractility of 

 the muscular system had been destroyed. The heart was the last portion of the 

 muscular system to yield to the effects of the poison ; it continued to beat feebly 

 for a short time. 



The blood from all parts of the body was of a brilliant scarlet color, and coagu- ^ 

 lated into a dense, firm clot, which was unstable and dissolved again. After the 

 dissolution of the fibrin, the blood-corpuscles settled to the bottom, and the serum 

 above was perfectly clear and without any marked color. Under the microscope, 

 the blood-corpuscles presented no unusual appearance when their broad surfaces 

 were turned towards the eye; when, however, they were viewed edgeways, they 

 appeared swollen, and the central nuclei were much less distinct than in their normal 

 condition, being scarcely visible. 



Acetic acid exerted its characteristic action, first rendering the blood-corpuscles 

 dumb-bell or hour-glass in shape, when viewed edgeways, and then rendering the 

 exterior cell-wall transparent, and bringing out clearly the nuclei. When the 

 acetic acid was neutralized with diluted liquor potassa, the cell-walls were again 

 brought into view. Concentrated liquor potassa dissolved the blood-corpuscles with 

 no immediate change of color. In a few moments, however, the color changed to 

 a darker red, and gradually assumed a brownish-yellow color, and became, as usual, 

 ropy and viscid. 



Vigorous streams of carbonic acid and oxygen gases, passed through separate 

 and the same portions of blood, produced no change whatever in the scarlet color 

 or form of the blood-corpuscles. 



Portions of this blood were kept for several weeks, and they still retained their 

 scarlet color, and did not undergo putrefaction. 



These reactions show that the change in the color of the blood was due, not to 

 an alteration of the forms of the blood-corpuscles, but to a permanent chemical 

 change of their coloring matter. Another effect of the carbonic oxide gas was to 

 render the fibrin unstable. 



This gas arrests oxidation, and the rapidity of its action shows the great im- 



