SECT. XXIII. THE SAP. 4of) 



and the spontaneous precipitation of the sap when 

 left exposed to the action of the air. But the ana- 

 lysis of Vauquelin was more minute. In the sap of 

 Fagus syhatica he found the following ingredients : 

 Water, acetate of lime, with excess of acid, acetate 

 of potass, gallic acid, tannin, mucous, and extrac- 

 tive matter, and acetate of alumina. In 103Q parts 

 of the sap of Ulmus campestris he found 1O27 parts 

 of water and volatile matter, Q'240 of acetate of 

 potass, ro6o of vegetable matter, 0796 of car- 

 bonate of lime, besides some slight indications of 

 the presence of sulphuric and muriatic acids ; and 

 at a later period of the season he found the vege- 

 table matter increased, and the carbonate of lime 

 and acetate of potass diminished.* 



From the above experiments, therefore, as well as Compos!-] 

 from those of other chemists, it is plain that the sap 

 consists of a great variety of ingredients, diifering in 

 different species of plants ; though there is too little 

 known concerning it to warrant the deduction of 

 any general conclusions, as the number of plants 

 whose sap has been hitherto analysed is yet but very 

 limited. It is the grand and principal source of 

 vegetable aliment, and may be regarded as being 

 somewhat analogous to the blood of animals. It is 

 not made use of by man, at least in its natural 

 state. But there are trees, such as the Birch, whose 

 sap may be manufactured into a very pleasant wine ; 



Ann. de Chim. vol. xxxi. p. 20. 



use. 



