EFFECTS OF RESPIRATION ON THE AIR. 395 



balloon ascents at an altitude of 7 miles, viz., loss of power in the arms and 

 legs, failure of vision, and syncope, were probably due to the sudden and 

 combined influence of cold, and an insufficient supply of oxygen. Less 

 marked phenomena characterize the condition known to Alpine climbers a- 

 the Mai cle montague. They appear, however, at much lower levels than in 

 aeronautic expeditions, on account, probably, of the muscular fatigue and 

 want of sleep undergone. The symptoms of the affection breath! essness, 

 nausea or vomiting, palpitation, exhaustion, feeling of coldness, humming in 

 the ears, and congestions of various parts, are usually experienced at a height 

 of about 12-14,000 feet, and ascents of these altitudes should not be under- 

 taken by those who suffer from disease of the heart, or who have a predisposi- 

 tion to apoplexy. The symptoms of the Mai de montague are attributed bv 

 M. Lortet to the great consumption of heat that takes place in order to develop 

 the amount of muscular force required. Nevertheless, both man and animals 

 are capable of accommodating themselves to the diminished atmospheric 

 pressure of great heights, the town of Potosi being 13,265 feet above the 

 level of the sea, Aucomarco 15,258 feet, and Deba 15,920 feet. 



313. The aeration of the blood may take place, not only by means of the 

 Lungs, but also in some degree through the medium of the Cutaneous surface. 

 In some of the lower tribes of animals, indeed, this is a very important part 

 of the respiratory process ; and even in certain Vertebrata the cutaneous 

 respiration is capable of supporting life for a considerable time. This is 

 especially the case in the Batrachia, whose skin is soft, thin, and moist; 

 and the effect is here the greater, since, from the small proportion of the 

 blood that has passed through the lungs, that which circulates through the 

 system is very imperfectly arterialized. By the experiments of Bischoff it 

 was ascertained that, even after the lungs of a Frog had been removed, a 

 quarter of a cubic inch of Carbonic acid was exhaled from the skin in the 

 course of eight hours. Experiments on the Human subject leave no room 

 for doubt, that a similar process is effected through the medium of his general 

 surface, although in a very inferior degree; for by confining the body iu a close 

 chamber, into which the products of cutaneous respiration could freely pass, 

 whilst the pulmonary respiration was measured by a distinct apparatus, Prof. 

 Scharling 1 believed he had ascertained that the proportion of Carbonic acid 

 given off by the Skin is from ^th to g^th of that exhaled from the Lungs 

 during the same period of time, or from 350 to 500 grains. The results ob- 

 tained by more recent observers, however, render it probable that Scharliug's 

 estimate was too high. Dr. Ed. Smith inclosed the whole of his body, except 

 the head, in a caoutchouc bag, passed a current of air through it, and collected 

 the Carbonic acid. The whole quantity obtained in Summer, including that 

 found in the air of the room, was 6 grains per hour, or somewhat more than 

 1 per cent, of the amount passing off by the Lungs. Reinhard, 2 who had 

 admirably constructed apparatus at his command, estimated it at from 34 to 

 35 grains per diem (2.23 grammes) ; and Aubert, 3 whose experiments appear 

 to have been very carefully conducted, estimates it at about 60 grains (4 

 grammes), a quantity that is not equivalent to per cent, of the amount 

 eliminated by the lungs (13-14,000 grains). Moreover, it has been observed, 

 not unfrequeutly, that the livid tint of the skin which supervenes in Asphyxia, 

 owing to the non-arterial ization of the blood in the lungs, has given place 

 after death to the fresh hue of health, owing to the reddening of the blood 

 in the cutaneous capillaries by the action of the atmosphere upon them ; and 

 it does not seem improbable that, in cases of obstruction to the due action of 



i Ann: der Chem. und Phnrm., 1846. 2 Zeitschrift fur Biologie, Bd. v, 1869, p. 37. 

 3 Pfluger's Archiv, Bd. vi, 1872, p. 539. 



