PRACTICAL PAPERS—Fire BLIGHT. 
405 
the Siberians, the Golden Russett and Tallman Sweet. These va¬ 
rieties are able to fortify against the shock of winter, but their 
smaller cells, and firmer fiber, are not so yielding to the sudden 
pressure of sap, as the less hardy, but almost blight exempt vari¬ 
eties. Take the tree as an organized body, with its cellular tissue, 
its powers of circulation, absorption, respiration and assimilation, 
and with these functions carried on harmoniously there is health. 
When these operations are partially or wholly suspended, there is 
rest, disease or death. Any sudden interference with these func¬ 
tions is more disastrous than gradual change, hence the effect of 
extreme and sudden changes of temperature, a “nipping frost,” or 
an unusual and unlooked for pressure of sap into the delicate cel¬ 
lular structure, causing extravasation, or letting out of this sap 
into improper channels, and vegetable apoplexy the result. I believe 
it a disease of the circulation, arising from rupture of the cellular 
tissue and decay of sap. It may begin in a leaf stem, and involve 
a whole branch, or it may appear in patches or in sections. The 
sources of this disease may be various, but there is first, a mechan¬ 
ical, and second,* a chemical change, and the presence of fungi an 
entirely subsequent phenomenon. 
Viewed in this light, fire blight is resolved into as simple a dis¬ 
ease as any other; its sudden appearance readily accounted for, 
and the remedy may be inferred to a certainty. The fact that it 
appears at special seasons, and in marked locations, where the soil 
and temperature favor a very rapid growth after a period of rest, 
causing a sudden push of sap, points directly to abnormal circula¬ 
tion ,, induced by these natural conditions, as the starting point of 
the disease. 
If these premises and conclusions are right, the remedy is 
to be found in securing the proper conditions of soil and climate. 
As our control of climate is very limited, we may only adapt 
our practice to it. The lake shore, the sea coast, and all countries 
where the temperature is made even from the influence of large 
bodies of water, are comparatively exempt from this disease. By 
choosing high lands, of medium fertility, avoiding stimulating 
manures, and with moderate culture, we may largely avoid the 
blight. Why the hills of the Granite State and the bluffs of 
central Wisconsin compete with the lake and sea coast in 
