388 CUTANEOUS SECRETIONS. 



quantities that we can form a decided opinion regarding the exis- 

 tence of acetic acid in sweat : we think it not improbable that it 

 occurs there. Berzelius considers that lactic acid is the free acid 

 of the sweat, and that it likewise is in combination with the am- 

 monia ; Berzelius has, however, not operated on such quantities ol 

 sweat as to have enabled him to determine this acid with his ordi- 

 nary accuracy. Since, according to my investigations, the secretion 

 of the sebaceous glands, even after saponitication, yields either nc 

 volatile fatty acids, or, at most, very small quantities of them, the 

 above mentioned volatile acids must of necessity pertain to the 

 secretion of the sudoriparous glands. 



The extractive matters, which afford so much annoyance to the 

 chemist, are of course present here ; from the facility with whicl: 

 the sweat decomposes, it is even more difficult to arrive at an} 

 definite conclusion regarding its extractive matters than regarding 

 those of many other animal fluids. Although we cannot recognise 

 amongst these substances any material which possesses the pro- 

 perties of a protein-body, a sulphurous matter must be contained 

 in the sweat ; for if we keep fluid sweat in a closed glass, we find 

 that a considerable quantity of sulphide of ammonium is formed as 

 soon as decomposition commences. 



The observations which have been made by physicians regard- 

 ing the qualitative and quantitative changes which the sweat un- 

 dergoes in diseases are of so uncertain a character, that we must 

 hesitate in basing any conclusions on them. Such observations 

 and conclusions as the following, namely, that as the sweat oJ 

 persons who perspire very copiously, as, for instance, of rheumatic 

 and arthritic patients, has a very distinctly acid reaction, therefore 

 rheumatism and arthritis depend on a lactic-acid dyscrasia or dia- 

 thesis, might have been well spared in medicine. We need hardly 

 observe that the increased acidity is in such cases dependent upon 

 the concentration of the sweat by evaporation. 



Anselmino maintains that he detected albumen in the " critical" 

 sweat of a patient with acute rheumatism. 



Urea* has not yet been found in the sweat; but it may probably 

 occur there in cases in which the blood is richer than usual in this 

 substance, and in which there is a very copious secretion of sweat. 



Wolff t thought that he had once detected uric acid in the dried 

 sweat from the forehead of a patient with calculus. 



* [Urea has been found in the sweat of healthy persons by Landerers (see 

 Arch. f. Chem. u. Mikros. Bd. 4, p. 196), and by Schottin, a pupil of Lehmann's, 

 in cases of renal disease (see Schmidt's Jahrb. Bd. 74, S. 9.) G. E. D.] 



f Diss. inaug. sing. cas. calculositatis. Tub. 1817. 



