724 



CHEMISTR Y OF RESPIRATION. 



Berg, 1 on the other hand, found the discharge of carbon dioxide considerably 

 diminished, but this has not been confirmed by Fubini, 2 AV!IO observed, in 

 comparative experiments, only a slight decrease in the output of carbon 

 dioxide after removal of the lungs. 



To all of these experiments there are certain objections. The varnish, 

 especially when containing alcohol, acts injuriously on the frog, and interferes 

 with its free movement; the removal of the lungs, apart from the actual injury 

 done to the animal during the operation, may cause the skin to take on 

 vicariously the function of respiration. Later experiments by King 3 are free 

 from these objections, for the head of a normal frog was passed through a 

 rubber collar into one part of a chamber, while the body was retained in the 

 other part the pulmonary and cutaneous respiration were thus determined 

 separately ; and in order to allow for the cutaneous respiration which would 

 take place on the head, other experiments were made, in which only the nose 

 projected, and in which section of the vagi nerves, an operation which suspends 

 the pulmonary respiration, had been performed. The results show that, during 

 the winter at least, the cutaneous respiration is far more important than the 

 pulmonary. 



Dissard 4 has determined the production of carbon dioxide after ligature of 

 the cutaneous or the pulmonary blood vessels of frogs, and he finds that both 

 cutaneous and pulmonary respiration are necessary to the animal, for the 



1 "Untersuch. ueber d. Hautathmung d. Frosches," Diss., Dorpat, 1868. 



2 Untcrsuch. z. Naturl. d. Mensch. u. d. Thicre, 1878, Bd. xii. S. 100. 



3 Arch. f. PhysioL, Leipzig, 1884, S. 183. 



4 Compt. rend. Acad. d. sc., Paris, 1893, tome cxvi. p. 1153. 



