CUTANEOUS EESPIEATION. 489 



consistent with, our views, locating the respiratory sense in 

 the general system. 1 



Cutaneous Respiration. 



This mode of respiration, though very important in 

 many of the lower orders of animals, is insignificant in the 

 human subject, and even more slight in animals covered 

 with hair or feathers. 2 Still, an appreciable quantity of 

 oxygen is absorbed by the skin of the human subject, 

 and an amount of carbonic acid, which is proportionately 

 larger, is exhaled. Exhalation of carbonic acid, which is 

 connected rather with the functions of the skin as a general 

 excreting organ and is by no means an essential part of the 

 respiratory process, will be more fully considered under the 

 head of excretion. Carbonic acid is given off with the general 

 emanations from the surface, being found at the same time 

 in solution in the urine and in most of the secretions. It is 

 well known that death follows the application of an imper- 

 meable coating to the entire cutaneous surface ; but this is 

 by no means due to a suppression of its respiratory function 

 alone. The skin has other offices, particularly in connection 

 with regulation of the animal temperature, which are infi- 

 nitely more important. 



An estimate of the extent of cutaneous, compared with 

 pulmonary respiration, has been made by Scharling, 3 by com- 



1 The physiological and pathological questions connected with the subject of 

 " respiration before birth," are ably and exhaustively discussed in a review pub- 

 lished in the Medico-Chirurgical Revieio, for April, 1864. A number of ex- 

 periments by various observers are here detailed, fully establishing the facts we 

 have stated. Among the most interesting are those of Schwartz, showing respi- 

 ratory movements in foetuses, when care was taken not to expose them to the 

 cool air or any other irritation of the general surface, p. 333. 



2 REGNAULT and REISET found the cutaneous respiration so slight in the ani- 

 mals which they used for their experiments, that its influence upon the compo- 

 sition of the air in which they were confined could be disregarded. (Op. tit.) 



3 In MILNE-EDWARDS, Lemons sur la Physiologic, tome ii., p. 635. The reader 

 will here find an account of the experiments of De Milly, Abernethy, and others, 

 demonstrating the absorption of oxygen and exhalation of carbonic acid by the skin. 



