92 The Potatoe Plague. 
corn, oats, hay, potatoes, &c., will not grow well there, even 
if they are supplied with the very best stable manure. They 
need ashes, lime, &c., in such places, and they cannot do with- 
out them. 
The fungi being composed principally of carbon, oxygen, 
and hydrogen, feed upon carbonic acid and water chiefly, and 
consequently if lime or potash be added to the soil where 
they grow, and the carbonic acid be thereby changed into a 
salt, the fungi have nothing to feed upon, and therefore die, 
for they cannot feed upon a salt. 
When the potatoe crop has been furnished with sufficient 
alkali, particularly potash, and the carbonic acid in it is in 
the form of a carbonate, the fungi have nothing to feed on, 
and do not attack the potatoe. On the other hand, when 
there is xot sufficient alkali given to the potatoe crop to cause 
the carbonic acid to form a salt by union with such alkali, 
then the carbonic acid in the potatoe is in its own form of 
earbonic acid, and as such the sickly root offers the proper 
food to the fungi, and it avails itself of it; unfortunately for 
doing so, it brings down upon itself the charge of being the 
cause of the potatoe disease.* 
The same is the case with other plants. Ifthey lack alkali 
to form a salt in connection with the carbonic acid they re- 
ceive, the superabundant carbonic acid will give nutrition to 
the seeds of fungi, and they will sprout and grow. We see 
this effect produced in wheat in the case of mildew, rust, or 
blight, and also smut in the same plant, the ergit in rye, the 
“ devil’s snuff-box” in corn, the mildew in oats, buckwheat 
—arenrnegemnenensraantmetettitmenpettersttititainneihtiniitten 
*Some of the practical chemists of this city, with their balances, tests, &c., 
might do the agricultural community a great service in connection with 
this matter, by analyzing sound potatoes, and giving their constituents ; 
and then analyzing the rotten potatoes, and giving their constituents also. 
The public might then compare them, and see what was wanted, and sup- 
ply it. 
