190 APPENDIX. [March, 



which gave it life. This is the beginning of putrefaction. Let us not 

 be deceived by a name. Putrefaction we always associate with dis- 

 gusting effluvia. But in the wide sense we have defined it, it includes 

 also the fragrance of new hay. Whenever bodies consist only of oxy- 

 gen, hydrogen, carbon, and a trace of azote, their putrefaction is fra- 

 grant, or inodorous ; when, in addition to these, bodies contain large 

 portions of azotized matter, gluten, albumen, or sulphur, and phos- 

 phorus, putrefaction evolves abominable odors. To the agriculturist, 

 putrefaction is always a wholesome process, beneficial to his best in- 

 terests, when promoted and controlled. There is only one case, where 

 this process produces loss. This may be termed destructive putrefac- 

 tion ; it is produced by heaping together green plants, or sometimes by 

 moistening dry vegetable substances. Here oxygen is rapidly absorbed, 

 and finally the mass takes fire, and burns. Up to the momentof inflam- 

 mation this is putrefaction. New hay, stacked too green, is a familiar 

 example. Volumes of steam are evolved, which proceed partly from the 

 decomposition of the plant ; decompositions, and recompositions rapidly 

 ensue; these are the ferment, which keeps up the action till the plants 

 burn. Doubtless, all green plants, ploughed in, undergo to a greater or 

 less extent destructive putrefaction, which succeeds the vinous and acid 

 fermentations, perhaps caused by the very rapidity of these processes. 

 Hence, in addition to the sugar, starch, and gum of the plant, we lose 

 a large portion of its other substances, by turning it in green. The 

 products of this rapid fermentation have been but little studied. Happy 

 the farmer who never M'^itnesses the process. He should never induce 

 it, and may generally prevent its extension, when once begun. It is a 

 dead loss to him ; but in all other cases of putrefaction, the products 

 are valuable. These vary according as the process takes place : 1st, 

 in air ; 2d, at the surface of the ground ; or, 3d, deep in the interior of 

 the earth. The last need not detain us — it produces all the varieties 

 of coal. 



1st. In the free air, having access to all parts of a plant, putrefac- 

 tion produces carbonic acid, nitric acid, and water. But ordinarily, 

 in the air, as oxygen does not find ready access to all parts, a portion 

 of the hydrogen of the plant combines then with the carbon, sulphur, 

 phosphorus and azote of the plant, and we have carburetted, sulphur- 

 etted, and phosphuretted hydrogen, and ammonia produced. Now, as 

 these exist but in small quantity in vegetables, the loss of hydrogen 

 will not be very great by drying the plants, and it is possible, that the 

 removal of these, may cause the other elements to enter into more 



