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 of 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 Hght, 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 to admit. 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 



