THE rLA:NT. 41 



Thej consist, as will be recollected, of carbon, hy- 

 drogen, oxygen and nitrogen^ or of all of the atmos- 

 j)herio elements of plants. They are all of much the 

 same character, though each kind of plant has its 

 peculiar form of this substance, which is known under 

 the general name oi protein. 



The protein of wheat is called gluten — that of In 

 dian corn is zein — that of beans and peas is legurain. 

 In other plants the protein substances are vegetable 

 alhuinen., casein.^ etc. 



Gluten absorbs large quantities of water, which 

 causes it to swell to a great size, and become full of 

 holes. Flour which contains much gluten, makes 

 light, porous bread, and is preferred by bakers, be- 

 cause it absorbs so large an amount of water. 



The nitrogenous substances are necessary to animal 

 and vegetable life, and none of our cultivated plants 

 will attain maturity, (complete their growth,) unless 

 allowed the materials required for forming them. To 

 furnish this condition is the chief object of nitrogen 

 given to plants as manure. If no nitrogen could be 

 obtained these substances could not be formed, and 

 the plant must cease to grow. 



When, on the contrary, ammonia is given to the 

 soil, (by rains or otherwise,) it furnishes nitrogen, 

 Avhile the carbonic acid and water yield the other 

 constituents of protein, and a healthy growth con- 

 tinues, provided that the soil contains the earthy 

 •natters required in the formation of the ash, in a 

 condition to be taken up by the roots. 



The wisdom of this provision is evident when wo 



