AMERICAN INSTITUTE. • 461 



sucli as opium, arsenic, or any alkaline or metallic poison, as they 

 will kill the tree or plant as readily as they will human beings. 

 Soluble matters are frequently imbibed by plants in an unaltered 

 state, In other cases they are decomposed during absorption. 

 Davy discovered that mint plants, which he forced to vegetate in 

 sugar and water, absorbed the sugar unaltered ; and it is an ascer- 

 tained fact that the spongioles and rootlets of plants will take 

 up in their systems or reject sundry earthy matters of a soil, in a 

 very astonishing manner. The roots of the persecaria for instance, 

 when placed in equal parts of a solution of gum and sugar, 

 absorbed thirty- six parts of the sugar, and only twenty-six of the 

 gum ; and when placed in precisely the same proportions of 

 glauber salt, common salt, and acetate of lime, it was found that 

 the roots separated these salts from the solution with perfect ease, 

 absorbing six parts of the glauber salt, ten parts of the common 

 salt, and not a particle of the acetate of lime. These facts are 

 particularly interesting as they account for the beneficial action 

 of liquid manures. 



The use of artificially prepared liquid matters is not well 

 understood in England or the United States, but thoroughly so in 

 France, Germany and China. In Germany all the excrements of 

 stall-fed cattle are swept into the underground cisterns, and mixed 

 with five or six times its bulk of water, according to 'the richness 

 of the excrement. Five cisterns are usually employed, of such 

 a size that they each require a week to fill ; and thus each has 

 four weeks to ferment in before the mass assumes a uniform con- 

 sistence. It is then removed upon the land by means of a 

 pump, hose, or water cart. German farmers all say that no 

 manures are so powerful in their operation as liquids, urine and 

 blood being invariably found the best. The ammoniacal jets of 

 urine have a certain stimulating power that appears to hasten 

 vegetation more rapidly than any other substances, and at the 

 same time produces more than double crops. However we may 

 view the question of liquid manure, a great field of research pre- 

 sents itself on all sides, and no investigation will pay the agri- 

 culturist better than the labor and thought he may bestow 

 upon it. 



