50 MANURES. 
acteristic and nauseous. Not even a tolerable syrup can 
be made of it in the ordinary way. 
3. The deleterious influence of nitrogenous manures 
upon sugar-producing plants, is to be ascribed, in part, 
also to undue stimulation, under the power of which the 
plants absorb not only more food than they can assimi- 
late, but other substances not their proper food. The 
ammonia enters into combination also with the fixed min- 
eral ingredients in the soil, which are thus largely absorbed. 
Thus by the action of these manures many salts are intro- 
duced into the circulation, which are not only foreign to 
the plant in its normal condition, but highly injurious to 
the constitution of the sugar. Among these the chlorides 
of sodium and potassium, and probably the sulphates, are 
said sometimes to be introduced into the juices of the 
Louisiana cane in sufficient quantity to impart to them the 
peculiar sensible qualities of those salts. Southern planters 
are well acquainted with the fact that the juice of canes 
grown upon new or recently cleared lands is almost un- 
crystaliizable (McCulloh, p. 580), and the same is true of 
sorghum grown under like conditions in the North. The 
cause seems to be the great absorptive power or avidity of 
the humus in such a soil for ammonia which it derives 
from the air. The ashes of the forest which previously 
covered it, furnish a superabundance of salts which the am- 
monia renders capable of speedy absorption. In soils from 
which the chloride of sodium or common salt is extracted, 
it imparts the property of deliquescence to the sugar, ren- 
dering crystallization extremely difficult and destroying 
the crystals after they are formed. Experiments with 
sorghum have been reported in which these and other 
qualities resulting from high or overfeeding, have been 
so predominant as to render the syrup in its usual raw 
state disagreeable to the taste and worthless for sugar. 
