78 AMPHIBIA. 



accidental neglect of changing the water. Tlie results of 

 placing tliem under running water were similar. In this case 

 they were confined in a sort of cage, and sunk in a river. 

 The effects of temperature in all these experiments were 

 amongst the most curious and interesting circumstances con- 

 nected with the inquiry. These results prove that the dura- 

 tion of life under water is in an inverse proportion to the 

 elevation of the temperature from S2 degrees to about 1 OT, 

 at which point the animals die almost instantly. But these 

 effects of temperature were found to be modified by an in- 

 crease of respiration, whether by their rising to the surface 

 and breathing the atmosphere, or by the quantity of aerated 

 water being increased. 



Such is a slight glance at the results obtained with refer- 

 ence to the cutaneous respiration carried on through the me- 

 dium of aerated water; and those connected with the atmo- 

 spheric respiration of the same surface are no less conclusive. 

 Six Frogs were taken for one of the experiments, and a liga- 

 ture tied with the most rigid compression round the neck, so 

 as to exclude any possible passage of air. One of these lived 

 twenty days in a damp atmosphere, whilst those which were 

 placed in five ounces and a half of water, died as soon as all 

 the air contained in that water was respired, which was in 

 from one to three days. Another experiment of correspond- 

 ing tenour was performed by the total excision of the lungs ; 

 and of three Frogs thus treated, two died on the thirty- 

 third, and one on the fortieth day. 



The results of other experiments proved that pulmonary 

 respiration alone is not sufficient to support life without the 

 aid of that of the cutaneous surface. 



It is very clear that this important function cannot be car- 

 ried on unless the surface be constantly kept in a moist state. 

 The branchiae of fishes and of Crustacea, and the lungs of all 

 pulmoniferous animals, equally require that the respiratory 



