40 NATURAL SCIENCE. JAN., 
for a long period by their impregnation with the balsam. The tree 
which, perhaps, above all others delights in the inundations of the 
forest is the wallaba. In this we have not only a secretion of tannin, 
but also an oleo-resin which impregnates the tree to its very heart. 
Others have similar balsams, while some are so impregnated with 
essential oils as to smell quite strong, although not always pleasant. 
These secretions make the Guiana timbers so valuable, as they endure 
longer under water than those from any other part of the world. 
Bitter extractives are found in the barks and seeds oi many trees. 
Simaruba and greenheart are well-known, as they may be found in the 
British Pharmacopcea. No doubt they are also protective, perhaps © 
chemically. Is it not possible that there is some truth in the old 
belief that medicines grow in every country suited to the disorders 
endemic to the place? The true explanation of this would be that 
plants protect themselves against evils which also affect man, and he, 
going to nature for a lesson, learns to follow their example. 
Protected against floods and excessive dampness by so many 
contrivances, the forest trees are able to secure moisture at all times 
without suffering from drought or flood. With such a wealth of 
rotting leaves about their roots, there is never any lack of plant food, 
and as for light, they have to struggle hard for that. In doing this 
we cannot help seeing that they are intensely selfish. We can 
hardly conceive of selfishness without a self—an individual—and 
that every tree, and even the humblest plant, is such the naturalist is 
bound toadmit. No matter that he cannot recognise one from another 
except in but few instances, the individuality is there and has been 
working for ages to raise the species to its present stage. According 
to the amount of individuality so will progress be greater or less. 
Heredity and environment may account for a great deal, but there 
is always something more than inherited traits and force of circum- 
stances. Evolutionists have apparently thought too much of species 
and too little of individuals. At some time or other the individual 
was father to the species, and a few of the present generation may 
be progenitors of new forms, the careful observation of which will 
give the naturalist of the future the strongest proofs of evolution. 
The tropical forest is undoubtedly made up of individuals. There 
is little of that apparent unison so common in temperate climates, 
where the trees open their leaf- and flower-buds together and at 
regular seasons. Here the ordinary observer says there are no 
seasons, but that trees flower and fruit all the year round. This, 
however, is an exaggerated statement not borne out by facts. There 
are two cycles in a year, the first in British Guiana commencing in 
February, and the second in August. As might naturally be 
expected, some species and varieties are earlier or later, and not only 
is this the case, but hardly two individuals flower, fruit, or drop 
their leaves at exactly the same time. This is most strikingly 
exemplified in the mango and other cultivated fruit trees. At the 
