ON THE QUANTITY AND QUALITY OF CROPS. 
311 
change of seed. Let us consider and examine at first a few observations 
which may serve to explain the phenomenon, and thence endeavour to 
deduce the physiological law, and apply it to the cultivation of trees. 
The advantages resulting from a change of seed are generally recog¬ 
nised in the cultivation of agricultural plants. In some mountainous 
countries, in Scotland for example, they bring the seed from the low 
countries and from the plains, where the climate is more mild, and, 
consequently, the seed is more forward, a quality which it preserves for 
several generations. We are convinced that the cultivator of this 
mountainous district, if he always used seed from his own crops, would 
reap later and later harvests, so that at last, perhaps, they would not 
come to perfect maturity ; a circumstance easily explained by the short 
duration of the summer in the mountains. If, on the other hand, the 
cultivator of a flat country, the climate of which is mild, and the soil 
dry and light, continually made use of his own seed, it would head every 
year sooner, the stalks would become shorter and smaller, and in time, 
there would result but a poor produce. In the last case, the cultivator 
brings his seed with advantage from a colder country, the soil of which 
is good and substantial. Probably these are the circumstances on which 
rests entirely the difference between the cereal and other plants of sum¬ 
mer and winter, a difference too variable to be easily determined. 
The flax, without doubt, presents us with the most striking example 
of this phenomena. We, in the neighbourhood of Liege, with great 
advantage to our crops, bring our seed from Riga, that is, from a 
colder climate, the sowing of which causes the grain to be slowly formed, 
and thus leaves more time for the development of the stalk, which is 
the principal object of its cultivation. To judge by analogy, we would 
be led to believe that the result would be the same, were we to obtain 
from a colder country and a colder soil, the grain of the clover and other 
plants used for forage, in the cultivation of which our object is large 
stalks and a well-developed foliage. Even at the present day we are 
without experience on this head. Generally all plants which are culti¬ 
vated for their grain or fruit, need little or no manure; while abund¬ 
ance is necessary for those plants from which we wish to obtain large 
stalks and leaves. 
Fruit trees which shoot vigorously, generally bear little or no ftuit ; 
and every circumstance, which on the other hand, prevents the too great 
growth of wood, favours the formation of fruit. On this observation 
rests the cultivation of dwarf fruit trees and espaliers; also that of the 
vine, &c. 
Field and culinary plants under equal circumstances blossom sooner 
