INTERNAL STRUCTURE OF PLANTS. 
31 
than that of the vegetabie ones. I only beg to remark, that 
the blood-globule (hloedskyfjes, blood-shields as the author 
calls them, which is a new Dutch word) of almost all animals 
are larger than the grains of chlorophyll. The muscular fibres 
of animals, on the other hand, are generally thinner than the 
spiral fibres. 
The inyention of M, Boucherie, of imparting useful qualities 
to wood, by causing different fluids to be imbibed by it, deserves 
mention at the conclusion of this department, (See Comptes 
Rendus, 1840, voL i, p, 686), The thought was suggested to 
him by the well known experiments, causing coloured fluids to 
be absorbed by, and to rise in the vessels of plants. Those ex- 
periments, which have hitherto been merely instituted for scien- 
tific purposes, he wishes to apply to purposes of general utility ; 
or, as he expresses himself, he is desirous of creating an indus- 
trial power from the vital power. The operation is performed 
on a tree which is still standing upright, by making a trans- 
verse incision, so as to bring the sap vessels in connection 
with the solution which the tree is to imbibe ; sufficient wood 
must, therefore, be left standing at two opposite points, so as 
to enable the tree to retain its vertical position. The absorbing 
power decreases on separating the tree from its roots {de sa 
souche), and from the moment of its being hewn down; use 
may, however, be still made of it for two days, or even for a 
longer period. This power, however, is different at different 
seasons ; it is strongest in the autumn. The quantity of fluid 
which is absorbed also varies very much ; but, as a general 
rule, it may be said, that the neutral combinations are imbibed 
in greater quantities than the acid amd alkaline. In order to 
render the wood durable, he causes the brown coal-tar (^pyro- 
lignite de fer') to be imbibed ; and to impart to it a greater 
flexibility and elasticity, he makes use of solutions of soluble 
chlorides, and the same are also useful in preventing the wood 
from being warped, and serve the purpose of rendering the 
wood less combustible. The dying of the wood is done by 
mineral or vegetable substances. If the former be used, the 
liquid already coloured must not be used, but hvo liquids 
must be applied successively, which produce colour by their 
423 
