CHEMICAL COMPOSITION OF PLANTS. 



107 



singault, and other chemists, to aid the botanist in his investigations, 

 and to place physiological science on a sound and firm basis. It is true 

 that many processes take place in plants which cannot as yet be ex- 

 plained by the chemist, and to these the name of vital has been applied. 

 This term, however, must be considered as implying nothing more 

 than that the function so called occurs in living bodies, and in the 

 present state of our knowledge is not reducible to ordinary chemical 

 or physical laws. A greater advance in science may clear up many 

 difficulties in regard to some of the vital functions, while others may 

 ever remain obscure. 



208. Plants are composed of certain chemical elements, which are 

 necessary for their growth. These are combined in various ways, so 

 as to form what have been called organic and inorganic compounds. 

 The former are composed of carbon, oxygen, hydrogen, and nitrogen 

 or azote, with a certain proportion of sulphur and phosphorus ; while 

 the latter consist of various metallic bases, combined with oxygen, 

 metalloids, and acids. In all plants there is a greater or less propor- 

 tion of water, the quantity of which is ascertained by drying at a 

 temperature a little above that of boiling water. By burning the 

 dried plant the organic constituents disappear, and the inorganic part 

 or the ash is left. The relative proportion of these constituents varies 

 in different species, as seen in the following table by Solly, in which 

 the proportions are given in 10,000 parts of the fresh plants: 



Water. Organic Matter. Inorganic. 



Potato, 7713 2173 . 114 



Turnip, 9308 588 . 104 



Sea Kale 9238 705 . 57 



French Beans 9317 619 . 64 



lied Beet 8501 1390 . 10'J 



Asparagus, 9210 735 . 55 



WaterCress, 9260 633 . 107 



Sorrel, 9207 702 . 91 



Parsley 8430 1299 . 271 



Fennel, 8761 1048 . 191 



Salsafy 7951 1929 . 120 



Mustard, 9462 436 102 



209. The analysis of 100 parts of Fruits gives the following results: 



Water. Organic. Inorganic. 



Strawberry 90-22 9'37 .... 0-41 



Green Gage, whole fruit 83'77 .. 15-83 .... 0'40 



Cherry, do., 82'48 .. 17'09 .... 0'43 



Pear, do,, 83'55 .. 16-04 .... 0'41 



Apple, do., 84-01 .. 15-72 .... 0'27 



Gooseberry, 90-26 .. 9'35 .... 0'39 



210. The following table, by Johnston, represents the constitution in 

 1000 parts of plants and seeds, taken in the state in which they are 



