328 
ON THE SHANKING OF GRAPES. 
only be affected by external agents inciting them to action. The uni¬ 
versal law of attraction is productive of results and combinations which, 
from the imperceptible processes in which they take place, are always 
more or less obscure. Currents of fluids are generated between evolv¬ 
ing and receptive bodies, which gain for the latter a character of self- 
action and inherent power which, in the case of plants, it is impossible 
they can either possess or deserve. 
In speaking or writing of vegetable development, therefore, it can¬ 
not be correct to assert that the roots can turn to the right or to the 
left; that the sap can ascend or descend ,* or that the shoots can 
lengthen themselves or remain stationary, as if they were endowed with 
a kind of volition like animals. The fact is, the causes of these move¬ 
ments and developments among vegetables are without , not within, the 
respective systems. The exciting causes are external, and the suscepti¬ 
bility of excitement is internal. Fermentative or elastic fluids, in 
expansible membranes, obey the stimulants of heat, air, and light, and 
conjointly exhibit all the phenomena of vegetation. 
ON THE SHANKING OF GRAPES. 
I am glad to see so many opinions upon this disease appear in your 
Register ; the point wants elucidation very much; and the gardener 
cannot be too observant, if he wishes to discover the origin of the 
complaint. 
I am sanguine enough to think, that what I am about to observe will 
throw a little light upon the subject. 
In page one of the March number (Vol. V.) is a communication 
from a Mr. Dale. He adopts the opinion of those who consider the 
disease to be caused by an oyer-moist, heated atmosphere (the excess of 
vapour being condensed, the water settles upon the footstalks of the 
bunches, which the sun acts upon as on a lens, and causes a scald upon 
the footstalk as much as hot-water would); hence the necessity of 
giving air by the top sashes early in the morning. Some practitioners 
have recommended keeping the house shut till all moisture arising 
either from sprinkling the evening before, or from the condensed 
vapour created by the morning sun, has disappeared. Air must be 
admitted some time, if there be any prospect of sunshine; and the 
earlier, the more natural. I have seen much damage done to grapes in 
a pine-stove by neglecting to give air when the foliage and fruit were 
wet with previous syringing; and undoubtedly this is one exciting 
cause; the leaving too large a crop is another: but the chief agent, as 
