SCIENCE-GOSSIP. 



205 



the starch. By a rearrangement of the molecules 

 the starch is converted into gum, or dextrine, and 

 finally into grape sugar. Such, in brief, is the 

 method by which the embryo plant is provided 

 with the means of subsistence. Observe that it 

 involves (1) the presence of flour, (2) that the flour 

 must be able to resist decomposing agencies until 

 required by the germinating embryo, and (3) that 

 it should be easily convertible into a fit condition 

 for the requirements of the plant. The plant 

 lives unconscious of the operation ; it has no share 

 in the prospective issues involved. The whole 

 process is necessary, invariable and infallible, due 

 to an original impression made upon its organs, 

 called instinct. 



As soon as the grain germinates, and root and 

 stem appear, each manifests its own properties. 

 The stem rises to the surface, and the root proceeds 

 downwards. The one seeks from the atmosphere 

 and the other from the soil the different elements 

 necessary for their existence. Their constitution 

 is even modified to suit their different functions. 

 The anatomy of the root is widely different from 

 that of the stem. However the seed is placed, or 

 whatever obstacles introduced, they cannot be 

 made to change their directions ; the stem will 

 rise and the root will descend. The experiments 

 of Duhamel prove this. Into a glass tube containing 

 some soil, introduce a bean — an ordinary haricot 

 bean, and through the glass watch the development 

 of the root and stem. Each obeys the law of its 

 being — the growth of the stem is upward and that 

 of the root is downward. Invert the glass, so 

 that the root may be uppermost, they will each 

 bend and resume their primitive directions. Re- 

 place the tube in its original position, and they will 

 again change their directions. Each inversion of 

 the tube is followed by a new inflexion of the root 

 and stem ; and if the room in which the experiment 

 is made is lighted on one side only, the stem will 

 turn towards the light and the root towards the 

 dark. Here are all the evidences of instinct, it 

 may almost be said of an energetic will. The cause 

 of the invincible obstinacy of these organs to 

 maintain their primitive directions is within and 

 not without the plant. 



A seed carried by the wind haply falls into a 

 cave where there is a scarcity of moist earth, the 

 air vitiated, and the light feeble ; in short, all the 

 elements necessary for germination, but of an 

 inferior quality. In that meagre soil, amid dark- 

 ness, and in the absence of fresh air, it notwith- 

 standing germinates and produces a plant. While 

 with a free supply of air, in a normal place 

 and in favourable conditions, the stem would be 

 short, thick, and coloured, in the cave, it is long, 

 slender, and blanched. It has stretched itself, as 

 it were, towards the aperture through which the 

 light and air are streaming in, if possible to procure 



from these elements a sufficiency of food to prevent 

 its dissolution in death. We can scarcely observe 

 without some feelings of misgiving its silent and 

 persistent efforts to obtain these coveted elements, 

 light and air. We may inquire, in view of these 

 facts, whether the plant is directed by an ex- 

 quisitely delicate sense peculiar to its kind, or 

 whether it obeys a general law, that the living 

 seek those conditions favourable to their healthy 

 development and perfection ? In either case, the 

 operations are instinctive. 



Passing to other facts. Here is a plant sup- 

 ported by the thin layer of soil that covers the 

 rock. No other situation, perhaps, could be more 

 unfavourable to the healthy growth and vigour of 

 its roots ; yet they develop, and that in such a 

 way as to excite our wonder. The roots insinuate 

 themselves into the fissures of the rock, and by a 

 series of gentle but continuous efforts, that delicate 

 root, of which the tissue is soft and spongy, 

 becomes an agent potent enough to split the rock. 

 It has achieved that gigantic task by the persistent 

 application of its tiny forces. So true is it, that 

 to triumph over an obstacle, that which effects 

 most is not the sudden and violent effort, but the 

 gentle and persistent one. Still, why so much 

 effort, and to what end such a result ? For answer, 

 follow the root in its track and the secret will be 

 soon learned. The root goes straight through the 

 stone to a tiny spring at its base. The huge rock 

 is unable to oppose forces powerful enough to 

 resist its gentle progress, and it must yield to 

 allow of a passage to the water. Have these tiny 

 roots a subtle scent or a delicate touch that leads 

 them so unerringly to the water ? Is the passage 

 through the rock not fatal, and of necessity, since 

 seeking the water they seek life ? 



We have not yet finished with vegetable nature, 

 but it is clear that plants possess instinct in its 

 two most striking forms — the preservation of the 

 individual and the species. 



In the wide range of plant phenomena few, 

 perhaps, are more interesting than those connected 

 with pollen and its dissemination. A complete 

 plant, it is well known, has two essential organs 

 destined to perpetuate the species. At the base of 

 the pistil is the ovary containing the ovules, while 

 at the apices of the stamens are small sacs or 

 anthers containing the pollen. The ovules to be 

 fecund must be fertilized with the pollen; this is 

 essential to insure the development of the fruit 

 and seed. Remove either the stamens or pistil 

 and the flower will die infructuose. The essential 

 organs are not always found on the same plant. 

 There are imperfect as well as perfect flowers, 

 otherwise male and female. The two sexes 

 may be found on the same or on different plants. 

 These latter need not necessarily be contiguous, 

 indeed they are sometimes separated by great 



