145 
tion of vigour may take place in tlie one, without any percep- 
tible alteration in the other. It is, therefore, the first object of 
the cultivator to proportion the supply of nutriment to the ex- 
tent of his tree, and this will be best effected by the shallow 
border above described.” 
164 Germination of Seeds. This subject is one which falls 
more or less frerjuently under the observation of all our readers, 
but the attention of all may not be alike directed to the interest- 
ing circumstances under which it takes place, and its attendant 
phenomena ; therefore, we purpose laying before our readers, 
information on this process of nature, as given by Professor 
Thomp.son, in his admirable work on the Chemistry of Vegeta- 
ble iiodies, p. 961. He says “Natural historians have proved, 
by a very complete induction of facts, that alt plants arise from 
seeds. The pretended exceptions have disappeared, one after 
another, as our knowledge of vegetables increased : and now 
there remains scarcely a single objection entitled to the smallest 
regard. The attempt of Girtanner to revive the doctrine of 
e(|uivocal generation, deserves no attention whatever; because 
bis conclusions are absolutely incompatible with the experi- 
ments of Mr. Sennebier upon the very substance on which his 
theory is founded. 
A seed consists of three parts ; namely the cotyledons, the 
radicle, and (he jilumula, which are usually enclosed in a cover. 
If we take a garden bean, we may perceive each of these three 
jiarts with great ease ; for this seed is of so large a size, that all 
its organs are exceedingly distinct. AVhen we strip off the ex- 
ternal coats of the bean, which are two, and of different degrees 
of thickness in different parts, we find that it easily divides 
into two lobes, pretty nearly of the same size and figure. Each 
of these lobes is called a cotyledon. The cotyledons of the 
bean, then, are two in number. Near that part of the lobes 
which is contiguous to what is called the eye of the bean, there 
is a small round white body, which comes out between the two 
lobes. This body is called the radicle. Attached to the radi- 
cle there is another small round body, whicb lies between the 
cotyledons, and wholly within them, so that it cannot be seen 
till they are separated from each other. This body is called 
the plumula. The apjiearance and shape of these three parts 
vary much in different seeds; but there is no seed which wants 
173 ADCTAKIOM. 
