CONSTITUENTS OF THE SWEAT. 387 



It must still remain very doubtful whether the fat which is 

 found in the sweat proceeds from the sudoriparous glands, or, 

 whether it only depends on the admixture of a little of the secre- 

 tion of the sebaceous glands. The fat of sweat that has been 

 collected in the ordinary manner has, in point of fact, precisely 

 the same physical and chemical properties as the fat of the seba- 

 ceous glands, as I have convinced myself by an examination of the 

 very profuse perspiration of a woman after delivery. Krause* has, 

 however, shown, by a very admirable experiment, that, in reality, 

 the sudoriparous glands themselves secrete true fat (together with 

 butyric acid, &c.) It is well known that there are no sebaceous 

 glands on the palm of the hand or the sole of the foot ; Krause 

 removed the fat and any loose epithelial scales from the palm of 

 the hand by ether and friction, and then covered a square inch of 

 it with a pad of filtering paper, from which all fatty matter had 

 been removed by ether ; this pad was firmly attached to the hollow 

 of the hand, and retained there for one night, being securely guarded 

 from external impurities ; a gentle perspiration was induced towards 

 morning; the paper, on being submitted to the action of ether, then 

 yielded a fat which, in addition to margarin, contained an oily 

 matter which rendered tissue paper distinctly transparent. 



We may further readily convince ourselves of the presence of 

 butyric acid in the sweat, by extracting with spirit textures tho- 

 roughly impregnated with sweat as, for in stance, stockings, flannels, 

 and other parts of the dress that have been worn next the body 

 and distilling the extract; we then saturate the acid distillate 

 with potash, evaporate, and decompose the salt with sulphuric acid, 

 when a most distinct odour of rancid butter is developed; I even 

 succeeded in obtaining the baryta salt, but the small quantity of 

 irregular crystals was insufficient to enable me to prove with cer- 

 tainty by micrometrical measurement, that the salt was butyrate of 

 baryta. If we can form an opinion from the odour of different 

 kinds of sweat, it is very probable that caproic and rnetacetonic 

 acids, which are closely allied to butyric acid, are also present ; in 

 many diseases, especially such as are accompanied by an acute 

 exanthematous eruption, there is often a singularly strong smell 

 of rnetacetonic acid. Anselmino and Simon have also detected acetic 

 acid in sweat by i'ts smell ; since this acid, if it actually occur in 

 the sweat, is always associated with other volatile acids of this 

 group, it cannot be determined with certainty by any of the known 

 tests for acetic acid : it is only by experimenting with very large 



* Op. cit. p. 14G. 



2 C 2 



