INTEGUMENTS. 



Mr. Cruikfhank's experiments prove clearly that there is 

 an oily matter fecreted by the (kin : indeed the familiar 

 appearance of the repulfion of water, fo as to caufe it to 

 ri-.n into globules, fufficiently evinces the faft. Mr. Cruik- 

 {hauk wore the fame veil of fleecy hofiery night and day 

 during tlie hotteft part of the fummer. At the end of this 

 time he always found an oily fubftance accumulated in con- 

 fiderable mafTes on the nap of the inner furface of the veft, 

 in the form of black tears. When rubbed on paper, it 

 makes it tranfparent, and hardens on it lilce, greal'c. It 

 burns with a white flame, leaving behind a charry re- 

 -fiduum. 



Bcfides the condenfablc vapour which is exhaled from 

 the flcin, it has been aiTerted* that gafcous fluids are alfo 

 feparated. Many philofophers have labotn-ed on this fub- 

 jccl, but the rcfults of their experiments are fo contradic- 

 tory, that we cannot deduce from them any very fatisfaiflory 

 conchifion. 



The count De Milly feems to have been the firft who 

 called the attention of philofop'ners to this fiibjeft. He 

 liiid often remarked the accumulation of fmall air-bubbles 

 on the furface of his body, wlicn immerfed in the warm 

 bath. At length, by means of a funnel and inverted glafs 

 jar he coUefted, in a few hours, half a French pint of the 

 gas, which was examined by Lavoifier. It was incapable 

 of fuppoiting combuilion, produced a precipitation in lime 

 water, and fuffcred no change from the admixture of nitrous 

 gas. Acad. Roy. des Sciences de Berlin, 1777. 



Mr. Criiikfhank found tliat a lighted taper, introduced 

 into a bottle in which his hand or foot had been con- 

 fined for fome time, burned dimly ; and lime water agitated 

 in it was rendered turbid. 



Ingenhouz could not procure the air from the flcin in 

 the warm bath in fuch quantity as the Count de Milly 

 did. What he collected feemed to be azotic gas. Expe- 

 riences fur les Vegetaux, t. i. 



Prieftley denies that any gas is perfpired by the fkin. He 

 repeated the experiments of Ingenhouz, and never could 

 obferve the appearance of gas arifing from the body when 

 he employed boiled rain water, from which the air had been 

 completely expelled, and detached the adhering bubbles 

 from his arm. He obferves that the air obtained by In- 

 genhouz "wasjuft that mixture of fixed air and partially 

 phlogillicated air, that pump-water, wliich he recommends 

 for the purpofe, generally abounds with." Experiments and 

 Obfervations, vol. v. p. 103. 



Fontana arrived at the fame coaclufion from his re- 

 fearches. 



Such alfo was the refult of Mr Jurine's jxperience, who, 

 after remaining in the bath at different temperatures from 

 18" to 30" of Reaurftur for hours together, never could pro- 

 cure a Angle bubble of air from his ilcin. He obtained 

 the fame refult from obfervations on feveral individuals in 

 water of various temperatures. Hilloire de la Societe 

 Royale de Medecine, torn. 10. 



Mr. Cruikfhank's experiments feemed to prove that air, 

 which has been confined for fome time -in contaft with the 

 Ikin, -becomes changed ; though Dr. Prieflley maintained 

 that the perfpirable matter has no fuch effedi on the air, 

 but leaves it as wholefome as ever. 



A very extenlive fet of experiments performed by Mr. 

 Jurine, of Geneva, and publithed in the volume already 

 quoted of the Memoirs of tiie Royal Society of Medicine, 

 feems to confirm tiie obfervation of Mr. Cruikfhaiik. Al- 

 though Mr. Jurine could not coliedl any air from his f!.;in, 

 whea immerfed in the v/arra bath, he always found the air 



confined about the flcin much vitiated. He fixed tvcII- 

 dried bottles under his arm-pits, and round his waiil, and 

 havino- left them there for an hour, accurately corked and 

 removed them, that the contained air might be examined 

 by the ufual tells. In thefe experiments he always em- 

 ployed the mercurial trough. This air was found, on dif- 

 ferent occafions, to contain .7, .7-:, .6, .4^ of carbonic 

 acid gas. He next inclofed his arm in a glafs cylinder 

 containing 6S5 cubic inches of air. One extremity of this 

 veffel clofely embraced his arm, round which it was cemented. 

 To the other extremity was fixed a bent tube, which, d'.iring 

 the experiment, was plunged under water in the pneumatic 

 trough. After two hours, the air of the cylinder was found 

 to contain .8 of carbonic acid gas. In another experi- 

 ment the fame quantity was Obtained after one hour ; but 

 the proportion of carbonic acid gas was not greater at the 

 end of two, three, or four hours. Being thus fatisfied 

 that carbonic acid gas is formed by the flvin when in contadt 

 with the»air of the atmofphere ; 4ie concluded, that he ihould 

 find the fame gas imder the bed clothes which confine the 

 air round the body during fleep ; and in experiments on 

 different individuals he found that this, air contained •4> 

 .6, .7, .55 of carbonic acid gas. 



In the fame volume are fome experiments by Gattoni, 

 which do not lead to the fame conclufions with thole of Ju- 

 rine : but they do not feem to have been very accurately per- 

 form.ed, and th.e tell of lime water was not employed. 



We come in the next place to the refearches of Mr. Aber- 

 nethy. From the hand, introduced into a glafs jar filled with 

 mercui-y and inverted, he collecled, in the fpace of fixteen 

 hours, one half-ounce meafure of air, whieh had efcaped 

 in fm-all bubbles from every point of the furface of tlie 

 imnfcrfed hand. Two-thirds of this gas were abforbed 

 by lime water ; and the remainder fuffered no diminution 

 from Ae admixture of nitrous gas. When the experiment 

 was repeated under water, a fmall quantity of azotic gas 

 only was obtained, the carbonic acid h.aving been, in the 

 opinion of Mr. Abernethy, abforbed by tRe water. The 

 hand was expofed five hours, in a jar containing feven 

 ounces of atmofpheric air, which was dim.inifhed about half 

 an ounce. One ounce of the remainder was abforbed by 

 lime water, with precipitation of the hme. By the tell of 

 nitrous gas the air was found to contain nearly ith lefs of 

 oxygenous gas than it did before the experiir.ent. V/hen a 

 fimilar experiment was performed with feven ounces of 

 azotic gas, rather more than one ounce meafure of carbonic 

 acid gas was produced in two iiours. The trials were re- 

 peated with hydrogenous, nitrous, and oxygenous gafcs, 

 and in every inllance nearly the fame quantity of carbonic 

 acid gas was obtained. 



In the 4 jth vol. (Sf the Annales de Chimic, there is a fhort 

 paper by Dr. Trouffct, who had noticed, like Milly, the 

 appearance of bubbles on the fltin in the warm bath. He 

 feems to have feen this only in two individuals, and found 

 the air to be perfectly pure nitrogen. In his own per- 

 fon, and in many others, he could obferve nothing of 

 the kind. 



Spallanzani is the lail experimental philofopher who has 

 paid particular attention to this fubjcft. The detail of 

 his experiments has not been publifiied, but the refults are 

 preferved in a letter to Senebicr, introduAory to the Me- 

 moirs on Refpiration. He appears to have been completely 

 fatisfied that air in contact with the fkin is changed exaAly 

 in the fame manner as by refpiration. When atmofpherical 

 air was employed, oxygen difappeared, and carbonic acid 

 gas was produced : he was of opinion, that the oxygib of 



the 



