RESPIRATION. 



We are indebted to Meffrs. Humboldt and Provencal tor 

 feme experiments on the reflation of fifties, winch ponels 

 Kreat accuracy. Their attention was firft d.reded to afcer- 

 tain the quantity and compofition of the air that exitte natu- 

 rally in river-water. For this purpofe, they filled glafs 

 balloons with given quantities of water, taken from the river 

 Seine, and expelled the air from it by fubmittmg it to ebul- 

 lition. The air that came over was received in veflels tilled 

 with mercury, or with dillilled water recently boiled, that 

 no foreign ai'r might mix with that obtained from the water 

 in the balloon. From the refults of ten experiments, eon- 

 duded in this manner, they found, that the water of the 

 Seine contained rather lefs than ^th of its volume of air. 

 This air they farther found to be compofed or about -^tiis 

 oxygen, with from 6 to 1 1 per cent, carbonic acid, and the 

 remainder was nitrogen gas. Mem. d'Arcueil, torn. u. 



Having thus determined the quantity and kind ot air con- 

 tained in a given volume of river -water, thefe chemids pro- 

 ceeded to afcertain the changes which it experienced by the 

 refpiration of fifties. With this view, they confined young 

 fifties in bell-glades of river-water, inverted over mercury ; 

 and fuffered them to remain till their refpiration became la- 

 borious. The animals were then withdrawn, and the water, 

 in which they had refpired, was transferred into the balloon, 

 and its air expelled, by fubmitting it to ebullition, m the 

 manner before ftated. Seven tenches were, in this manner, 

 confined in 4000 cubic centimeters, equal to 250.5 cubic 

 inches of river-water, where they remained eight hours and 

 a half. A portion of this water, equal to 2582 cubic cen- 

 timeters, or 1 61. 5 cubic inches, was then transferred from 

 the glafs-bell into the balloon, and its air expelled by heat. 

 The air, thus obtained, neafured 453 part*, at temperature 

 co° Fahrenheit. Thefe 453 parts were then wafiied in lime- 

 water, by which they were reduced to 300, fo that 153 parts 

 of carbonic acid were thus removed. The refidue was after- 

 wards analyfcd by combuftion with hydrogen, and by mix- 

 ture with nitrous gas ; and the means of three analytes af- 

 forded 0.035 of °*yg cn ? wherefore it is concluded, that the 

 ac* parts of air, obtained from water which had been in con- 

 tact with the refpiratory organs of fillies, confined of 

 10.5 oxygen, 289.5 nitrogen, and 153.0 carbonic acid gas. 

 But by former experiments, it was found, that an equal 

 volume of pure river-water afforded 524 parts of air, con- 

 lifting of 155.9 oxygen, 347-1 nitrogen, and 21.0 carbonic 

 acid ; confequently, fay thefe chemifts, thefe feven tenches 

 have abforbed, in eight hours, 145.4 of oxygen, and 57.6 

 of nitrogen gas; and they have produced in the fame time 132 

 parts of carbonic acid. (Mem. d'Arcueil, t. 11. p. 376.) 

 Mr. Ellis has pointed out feme fources of fallacy, from 

 which thefe apparent refults may have arifen, and it 

 is probable from analyfis, that in fifties, as in other ani- 

 mals, the change produced by refpiration is the converfiou 

 of oxygen into an equivalent portion of carbonic acid. 



The changes which the air undergoes from the refpiration 

 of Reptiles are detailed in that article. Its alterations 

 in the breathing of mammalia and birds are the fame as in 



ma »'The preceding fads," fays Mr. Ellis, « fufneiently 

 fhew, that various animals, in all the foregoing claffes, and 

 in every ftage and form of their exiftence, require the pre- 

 fence of oxygen gas to maintain the funaions of life ; that 

 this gas, by the exercife of thefe funftions, is converted into 

 carbonic acid : and that the degree in which this converfion 

 proceeds, depends much on the healthy condition of the 

 animal, and the vigour of its circulating tyftem. Since, 

 alfo, in every inftance where the experiments have been 



made with the requifite accuracy, the bulk of carbonic acid 

 produced, nearly or exactly equalled that of the oxygen 

 which difappeared, we may conclude, from analogy, that 

 fuch is universally the extent to which this change in the air 

 takes place in animal refpiration ; and fince, farther, the 

 nitrogen gas of the air appears to tuffer no neceffary change 

 in the exercife of this function, we may alio conclude, that, 

 as far as regards the air, the fubftitution of an equal bulk of 

 carbonic acid for the oxygen gas that is loft, comprifes the 

 only effential change which the atmofphere experiences during 

 the performance of this animal procefs. We have before 

 maintained that the oxygen of the air does not enter the ani- 

 mal fyftem, either by the living function of abforption, or 

 by the operation of chemical affinity ; and have conlequently 

 concluded, that the union of this iubilance with the animal 

 carbon takes place exterior to the veflels of the living 

 animal." Further Inquiry, p. 271. 



minimal Heat. — Taking the fpecific caloric of water at 

 1. 0000, Dr. Crawford found that of arterial blood to be 

 1.0300, and that of venous blood 0.8928 ; that of oxygen 

 gas compared to water, as 4.749010 1.0000; of nitrogen, 

 0.7936; atmofpheric air, 1.7900; and of carbonic acid 

 gas, 1.6454. The P ower °f oxygen gas to fupply heat, 

 fays Mr. Berthollet, is well known, and there is no fub- 

 fiance which fuffers fo much of it to efcape in the changes of 

 its conftitution. 



In the refpiration of animals, as well as in the germination 

 of feeds, and the vegetation of plants, the oxygen gas of 

 the atmofphere is converted into carbonic acid. Since the fpe- 

 cific caloric of the latter is little more than one-third of that 

 which the oxygen gas itfelf previoufly contained, it necef- 

 farily follows, that a large quantity of caloric is liberated, 

 whenever this converfion of gafes takes place. Now, in the 

 living proceffes jult alluded to, the prefencc of caloric is 

 very obvious : we refer for proofs on thefe fubjeCts, to the 

 articles Heat, slnimal, Mammalia, Birds, Fishes, In- 

 sects. Reptiles, and Vermes, in which the fads con- 

 nected with their vital temperature are detailed ; alfo to the 

 two " Inquiries" of Mr. Ellis. 



Since, then, all animals pofl'efs a temperature exceeding 

 that of the medium which they inhabit, and fince this, in 

 man and the fupcrior animals, varies but little under every vi- 

 ciffitude of heat and cold, confident with the due per- 

 formance of the animal functions, there muftexiftin all cafes 

 appropriate means of fudaining this function. But no living 

 powers of the animal fydem arc fufficient for this purpofe, 

 independent of the concurring aid of external agents. No 

 fuppofed attrition between the contiguous foft parts of the 

 animal ; no fridtion between the veflels and globules of the 

 blood ; no adtion of the folid parts upon one another ; no 

 circumftances arifing out of digeftion or fermentation in the 

 living body ; no imagined combudion of phofphorus in the 

 blood ; no liberation of the phlogiftic or any other princi- 

 ple, through the fydem, can be received as tuflicient to ac- 

 count for the uniform height and fteadinefs of this tempera- 

 ture. As, therefore, the animal fyftein, by virtue of its 

 own powers, is unable, within itfelf, to produce this high 

 degree of heat, to what external agent fhall we have recourfe, 

 and to what organs fhall we refer the production of that 

 more or lefs elevated temperature which is obfervable in all 

 animals. 



Infects, worms, and fifties, which have no refpiratory 

 ftructure fimilar to that of the lungs ; and reptiles, the fur- 

 face of whofe lungs, in proportion to that of the body, is 

 comparatively fmall, and whofe blood, at each circulation, is 

 but partially expofed to the influence of the air, pollefs a. 

 I 2 degree 



