vinegar (another kind of bacteria) attacks the alcohol and 

 converts it into an acid which we call vinegar. 



Similar forms of Hfe are at work, under warm, favorable 

 conditions, in the soil, preparing plant food for assimilation. 

 Not only are warmth and the right proportion of moisture nec- 

 essary for their growth, but the soil must be neutral or slightly 

 alkaline for their highest development. In order to produce 

 this condition, an application of quicklime or unleached wood 

 ashes is frequently necessary to correct any acidity of the soil 

 resulting from organic acids which are produced under certain 

 soil conditions. 



All organic matter or substances which have been at some 

 time organized into plants by the life force, such as leaves, 

 roots, stems, etc., must decay before they can nourish, that is, 

 before they can be absorbed and reorganized again into growing 

 crops. Stable manure contains a small amount of soluble salts 

 which are immediately ready to feed the crop, but the bulk of the 

 manure must rot down through the influence of bacterial action 

 before it becomes food; and the process of decay, or rot, is largely 

 the result of the growth of lower forms of life, or "yeast plants," 

 in the manure or in the soil, which, as we have seen, are depen- 

 dent upon certain favorable conditions. 



There are several known forms of nitrogen organisms in 

 the soil, two that are well defined, the de-nitrifying and the 

 nitrifying — the destructive and the constructive. Touching 

 the various organisms. Professor Stone, of the Massachusetts 

 Agricultural College, writes: 



"The de-nitrifying organisms are those which convert nitrates 

 into nitrites and ammonia. The nitrifying organisms are those which 

 convert ammonia into nitrites and nitrates. The latter are exceedingly 

 beneficial, while the former are not considered so, as plant food must 

 be in the form of nitrates. We never find nitrites in plants. There is 

 another type of organism known as nitrogen fixation organisms, and which 

 are represented by the organisms in legume nodules; also by many free 

 organisms which exist in the soil. We do not know much about these 

 organisms, but we do know that there are quite a number of them. Some 

 of them appear to work better when living with other organisms than 

 when isolated by themselves. There is evidence to show that a large 

 number of organisms have the power of fixing nitrogen in the soil; for 

 example, besides the species of clover bacteria, there is evidence to show 

 that many of the algae which live in the soil and certain molds will do the 

 same thing. In our work here, we find the largest percentage of nitro- 

 gen in those solutions which are contaminated with the blue bread mold 



23 



Lime 

 Helps 



Decaying 



Organic 



Matter 



Nitrifying 

 and 



De-nitrify- 

 ing 

 Organisms 



