FARMEES' INSTITUTES. 233 



into active fermentation, the decomposing manure begets a like action in the 

 nmck ; the ammonia, which would CJ-cape if the manure were fermented alone, 

 is retained by the muck, and the final re.=ult is 4 or 5 times the quantity of 

 manure that would have been obtained without the muck, and equal in quality, 

 bulk for bulk, to the manure furnished without such composting. But I only 

 drop a hint on this subject. Prof. Gulley, who has accomplished such wonder- 

 ful results with this material, will tell the farmers more about this suljject, and 

 I gladly leave the matter in such able hands. 



Another use of muck is to deodorize and preserve in an inoffensive form the 

 raanural matter derived from dead animals. When a dead animal is properly 

 covered with muck, no offensi^■e gases escape, and all the manural matters are 

 preserved. Here is some muck which has thus been used, and you observe that 

 it is not offensive to siglit or smell. So also when night soil is composted with 

 muck, a very powerful manure is formed in which all the disgusting qualities 

 of the original material have passed beyond the reach of sight and smell. 



NITRIFICATION. 



But the most interesting consideration in regard to muck is its possibility of 

 furnishing a vast store of available nitrogen for the use of plants. 



Many years ago it was supposed that the organic matter of soil was the prin- 

 cipal source of the organic matter of plants, — that it was in fact the special 

 food of plants. Analogy was in favor of this vicAV, for a carnivorous animal is 

 best sustained by animal food, i. e., food which has once passed the rounds of 

 animal life ; why should not a vegetable be also best fed by vegetable food, i, e., 

 material which has once passed through the rounds of vegetable life. But this 

 theory received a fatal blow when it was shown that a plant might make perfect 

 growth in a soil entirely destitute of organic matter. Liebig announced the law 

 that plants live entirely on inorganic matter, and are incapable of absorbing 

 and assimilating organic matter ; and he has carried the great mass of chemists 

 along with him. He taught that a plant could only absorb and assimilate car- 

 bon in the form of carbonic acid, and that the plant could not derive its organic 

 material directly from the humus of the soil ; that the jila-nt could assimilate 

 nitrogen only in the form of ammonia and the nitrates. That a plant can 

 make use of nitrogen when in these forms is conceded by every chemist, but 

 the question is now raised whether a plant may not oljtain nitrogen from vege- 

 table mold without its first passing into the form of ammonia or the nitrates. 

 This is a more difficult problem to solve than appears at first sight, because the 

 formation of ammonia or nitrates may go on all tlie while in soils charged with 

 vegetable matter if the conditions in regard to heat and moisture are favorable 

 to vegetable growth, and the question still remains whether the plant does not 

 even then derive its nitrogen from ammonia and nitrates. Prof. Storer has 

 lately published in the Bulletin of the Bussey Institution a very valuable article 

 "On the importance as plant food of the nitrogen of vegetable mold." He 

 claims that plants derive a large part of their nitrogen from vegetable mold, 

 and that plants make a fair growth when vegetable mold is the only available 

 source of nitrogen. Fields which have never been manured produce crops, and 

 the wild plants of the forest derive most of their nitrogen from vegetable mold. 



But that tliis supply of nitrogen is not suft^icient for the use of the plant is 

 shown in the fact that the growth of these jolants is greatly increased by a dose 

 of some nitrate. Even if the vegetable mold is such a source of nitrogen as to 

 enable the soil to bear fair crops, tliis does not satisfy the farmer. He wants 



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