C 107 3 



ed to almost any extent. No two compounds procured 

 from different vegetables are precisely afike , and 

 there are even differences in the qualities of the same 

 compound, according to the time in which it has been 

 collected, and the manner in which it has been pre- 

 pared : the great use of classification in science is to 

 assist the memory ; and it ought to be founded upon 

 the similarity of properties which are distinct, charac- 

 teristic, and invariable. 



The analysis of any substance containing mix- 

 tures of the different vegetable principles, may be 

 made in such a manner as is necessary for the views 

 of the agriculturist with facility. A given quantity, 

 say 200 grains, of the substance should be powdered, 

 made into a paste or mass, with a small quantity of 

 water, and kneaded in the hands, or rubbed in a mor- 

 tar for some time under cold water ; if it contain 

 much gluten, that principle will separate in a coherent 

 mass. After this process, whether it has afforded 

 gluten or not, it should be kept in contact with half a 

 pint of cold water for three or four hours, being oc- 

 casionally rubbed or agitated : the solid matter should 

 be separated from the fluid by means of blotting pa- 

 per : the fluid should be gradually heated ; if any 

 flakes appear, they are to be separated by the same 

 means as the solid matter in the last process, i. e. by 

 filtration. The fluid is then to be evaporated to dry- 

 ness. The matter obtained is to be examined by ap- 

 plying moist paper, tinged with red cabbage juice, or 

 violet juice to it ; if the paper become fed, it contains 

 acid matter ; if it become green, alkaline matter ; and 



