168 



The human body resists, without any effort, the atmospherical pres- 

 sure, because it is applied at all times, and in every direction. But if 

 a part of its surface ceases, for a moment, to be under its influence, it 

 swells, the fluids are determined to it, in considerable quantity, the in- 

 teguments become excessively distended, so as to be in danger of burst- 

 height of fourteen or fifteen hundred toises. Those who are less accustomed to the 

 air of the mountains, are obliged to rest much more frequently. So intolerable, indeed, 

 is the fatigue induced in this situation, that the person suffering it, is rendered some- 

 times wholly incapable of motion. If he attempt to move, his legs sink under him, his 

 heart palpitates, his arteries throb, his head becomes g'iddy, his eyes are dazzled, and, 

 to avoid fainting, he is forced to sit doww. Near the top of Mont Blanc, our traveller 

 could not advance more than a few steps without stopping to respire, and on the sum- 

 mit of it, though his exertions were moderate, he was constrained frequently to desist 

 altogether from them, and breathe laboriously to recruit his strength. With this exces- 

 sive degree of fatigue, accelerated pulse, and difficult respiration, there is great thirst, 

 sickness of stomach, a loathing of food, and an aversion to every species of spirituous 

 liquor. But what is very extraordinary, these affections are as short in their duration, 

 as they are violent. 



These effects are not peculiar to the human species. The same writer relates, that 

 the mules which tie employed to carry his baggage, became suddenly so weak and ex- 

 hausted that they could hardly walk, even when the burden was removed from their 

 backs. They staggered as they moved ; their respiration was panting and difficult, and 

 seemingly attended with painful sensations of the chest, as they uttered plaintive and 

 distressing cries. 



After resting a few minutes, the sense of fatigue is so completely dissipated, tbat the 

 person, in resuming his journey, feels such a renovation, that he is persuaded he will 

 be able to prosecute it uninterruptedly. He, however, is soon disappointed. On 

 moving a short distance only, his former inability returns, and his progress is again ar- 

 rested. An additional effect of this state of the atmosphere, is an almost irresistible 

 propensity to sleep. We are told, that if the attention of the person be not engaged, 

 and kept excited, he will, wh<>n pausing to rest, often fall to sleep almost instantane- 

 ously, though annoyed by the wind or cold, the light or heat of the sun, and in the 

 most incommodious and disagreeable posture of his body. This sleep sometimes, ap- 

 proaches in soundness nearly to lethargy. It may also be observed, that aeronauts have 

 generally mentioned drowsiness as one" of the consequences produced by the attenu- 

 ated atmosphere of the exalted regions which they explore in their excursive flights, 

 and some have even declared that they slept soundly, when at the utmost pitch of their 

 perilous adventures. 



Nothing affords the least relief to any of the symptoms enumerated, except rest and 

 cold -water. Cordials and spirituous liquors aggravate all the complaints. 



Now, in what manner are these singular affections to be explained ? We believe, 

 with our author, that they are in part owing to the diminished pressure of the atmo- 

 sphere, but infinitely more to a deficiency of oxygen. 



It is clearly ascertained, that respiration supports animal life, and all its actions. This 

 process requires the presence of two principles. These are oxygen and combustible 

 matter. The former is supplied chiefly through the medium of the lungs, and the lat- 

 ter by the stomach. Of the vital actions, none seems to be more immediately depem 

 ent and strikingly regulated by respiration than the muscular. It is not, however, my 

 design to dwell on the relation between them. It is sufficient for my purpose to re- 

 mark, that during exercise a greater quantity of oxygen is extracted from the atmosphere 

 by the lungs, and that carbonic acid and water are formed, and caloric evolved in cor- 

 responding proportions. Hence it may be deduced, that during muscular exertion, 

 there is a greater demand for oxygen, and a larger consumption of combustible matter. It 

 also follows, that if the preceding premises be admitted, as a legitimate corollary, that 

 the same effect would be produced, namely, an exhaustion of the muscular vigour, by 

 withholding the one or the other of these agents. In either case, fatigue will be caused, 

 and the body rendered incapable of muscular exertion. But the incapacity in the two 

 :s arises from different states of the svstem, and will be distinguished by different 



cases ases 



appearances, and removed by different methods of treatment. 



Limited exercise in an atmosphere of sufficient density, slowly deprives the body oi 

 its proper quantity of combustible matter, until fatigue is finally induced. The body 

 is afterwards gradually recruit-rt by rest and food, or directly restored to momentary 



