94 



carbon, hydrogen, oxygen, nitrogen, sulphur, phos- 

 phorus, acids, alkahes, earths, and metals are the 

 common components of both. Nitrogen has been 

 considered by some chemists as the constituent, 

 marking by its presence animal from vegetable mat- 

 ters ; but the distinction fails, inasmuch as that from 

 some animal matters it is absent ; whilst in the gluten 

 of plants — a chief constituent of wheat — in all seeds, 

 and in the whole frame of the tobacco, it is present. 



If we follow the above chemical bodies through 

 their combinations, we shall find tbat these in animals 

 and plants are closely similar, and in both are equally 

 numerous and intricate. 



Of acids there are contained in 



and others equally numerous in each, but not common 

 to both. Of the earths and alkalis, lime, magnesia, 

 silica, soda, and potass, are found in each class. Of 

 the metals, iron and manganese are their conjoint 

 constituents. 



If we follow the two classes through their more 

 compound constituents, we shall find the analogy still 



ANIMALS. 



1. Sulphuric 



2. Phosphoric 



3. Muriatic 



4. Carbonic 



5. Benzoic 



6. Oxalic 



7. Acetic 



8. Malic 



VEGETABLES. 



1. Sulphuric 



2. Phosphoric 



3. Muriatic 



4. Carbonic 



5. Benzoic 



6. Oxalic 



7. Acetic 

 y. MaUc 



