112 BOARD OF AGRICULTURE. 



arrested at the proper stage, as otherwise the changes attending it 

 ■would result in damage and loss. In such sweating, -which is a par- 

 tial fermentation, there take place manj different chemical changes, 

 which together w ith their effects are more fuUj set forth than I have 

 ever seen elsewhere, in a communication received from Dr. Samuel 

 L. Dana, well known as a distinguished chemist, in replj to a note 

 of inquiry touching this matter, and which is as follows : 



" Growing' grass is a mass of ferments and fermentable principles, 

 combined with neutral substances and mineral matters. By fer- 

 ments, I mean matter capable of exciting- fermentation. By fer- 

 mentation, I mean a change in the state of a body attended with 

 production of carbonic acid and alcohol. By fermentable principles, 

 I mean bodies capable of undergoing fermentation ; or simplj^ a 

 change without loss of substance. B}^ neutral principles, I mean 

 fatty and waxy matter. By mineral substances, I mean the earths 

 and salts, wdiich form the ash of burned grass. 



The elements above enumerated form the skeleton of the grass, 

 which is clothed with green drapery, composed of a neutral sub- 

 stance, which like the coloring matter of blood contains iron as one 

 of its components. The whole plant is rendered plump and soft 

 by an excess of water — the sap of the vegetable. 



The ferments are composed of -four chemical elements — carbon, 

 oxygen, hj^drogen, and nitrogen. They form a distinct group, 

 composed of albumen, gluten, &c., imited to sulphur and i)hos- 

 phorus. 



The fermentable matters also form a distinct group of well defined 

 vegetable principles, all connected by a common bond, and behaving 

 much alike under similar circumstances. This group comprises: 



1. Woody fibre. 



2. Starchy matter. 



3. Gummy matter. 



4. Sugary matter. 



These are composed of carbon, hydrogen and oxygen, only the 

 last two being in just the propoiiion to form w' ater. 



5. Jelly matter composed like the above, but with oxygen in 

 excess. 



If the members of these two groups were in a perfectly dry state, 

 no change w^ould occur. The}' are capable of acting on each other 



