172 
October, and are then taken up and potted, and placed in a 
cold frame, where they remain through the winter. 
The grafting wax used for covering this giaft is composed as 
follows; — Burgundy pitch, 1 lb.; black pitch, 4 oz.; rosin, 2 
oz.; yellow wax, 2 oz.; tallow, or suet, oz. The whole 
melted together, and, after being allowed to cool, it is used 
when rather less than milk-warm. 
176 Food of Plants. In a former part of the Auctarium, we 
inserted some interesting remarks on Germination from the late 
work of Dr. Thompson, on the Chemistry of Organic bodies, 
a treatise which we recommend to such persons as feel an inter- 
est in the chemistry of vegetables. AVe will here extract a por- 
tion of his observations on tlie Food of Plants. He says. 
“ Plants after they have germinated, do not remain stationary, 
but are continually increasing in size. A tree, for instance, 
every season adds considerably to its former bulk. The root 
sends forth new shoots, and the old ones become larger and 
thicker. The same increment takes place in the branches and 
the trunk. AVhen we examine this increase more minutely, we 
find that a new layer of wood or rather of alburnum, has been 
added to the tree in every part, and this addition has been made 
just under the bark. Vfe find too that a layer of alburnum 
has assumed the appearance of perfect wood. Duhamel has 
shown also that a new layer of liber next to the alburnum, is 
formed every year. Besides this addition of vegetable fibre, a 
great number of leaves have been produced, and the tree puts 
forth flowers and forms seeds. It is evident from all this, that 
a great deal of new matter is continually making its appearance 
in plants. Hence, since it would be absurd to suppose that 
they create new matter, it must follow that they receive it by 
some channel or other. Plants, then, require food as well as 
animals. Now, what is this food, and whence do they derive 
it ? These questions can only be answered by an attentive sur- 
vey of the substances which are contained in vegetables, and 
an examination of those substances which are necessary for 
their vegetation. If we could succeed completely, it would 
throw a great deal of light upon the nature of soils, and of ma- 
nures, and on some of the most important questions in agricul- 
ture. But we are far indeed at present from being able to 
examine the subject to the bottom. 
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