LIQUID PARTS OF ANIMALS. 



him to a distance by the scent. A dog chained for some hours 

 after his master had set out on a journey of some hundred miles, 

 followed his footsteps by the smell, and found him on the third 

 day in the midst of a crowd.* Mr Cruikshanks, to discover the 

 nature of this substance, wore for a month the same vest of fleecy 

 hosiery during the hottest part of the summer. He found an 

 oily-looking substance accumulated in considerable masses on 

 the nap of the inner surface of the vest, in the form of black 

 tears. When rubbed on paper it rendered it transparent, and 

 gave it a greasy stain. It burnt with flame, leaving a charcoal 

 behind it.f 



Thenard repeated this experiment of Cruikshanks in 18064 

 A flannel jacket, previously well washed in distilled water and 

 dried, was worn for ten days next the skin below a linen shirt. 

 It was then washed in pure water, and the aqueous liquor was 

 distilled in a retort. The liquid that came over had the smell of 

 sweat, and contained a small quantity of acetic acid. The liquid 

 remaining in the retort, when sufficiently concentrated, assumed 

 the appearance of an acid syrup, which contained common salt ; 

 but no salt of lime. It was sparingly precipitated by infusion of 

 nut-galls. Thenard concluded, from his experiments, that the 

 matter of perspiration, besides water, common salt, and acetic 

 acid, contains a little phosphate of soda, traces of phosphate of 

 lime and of iron, and an animal substance precipitated by infu- 

 sion of nut-galls ; probably albumen. 



The most recent experiments on the matter of perspiration have 

 been made by Anselmino. He plunged his arm into a glass 

 jar, and luted the mouth of it to the arm below the shoulder. 

 The matter perspired condensed on the inside of the glass as in 

 Cruikshanks's experiment, and in six hours he collected a table- 

 spoonful of it. He divided the liquor thus obtained into three 

 portions, and subjected them to the following trials : 



1. One portion was mixed with a drop of sulphuric acid and 

 then evaporated to dryness, This residue was mixed with a little 

 caustic potash, and a glass rod dipped in muriatic acid was held 

 over it. Evident fumes of sal-ammoniac made their appearance ; 

 showing that ammonia existed as one of the constituents of mat- 

 ter of perspiration. 



* Cruikshanks on Insensible Perspiration, p. 93. f Ibid. p. 92. 

 t Ann. de Cbim. lix. 262. Berzelius, Traite de Chimie, vii. 328. 



