270 



THE YOUNG NATURALIST. 



for digestion the mineral constituents of its 

 diet. Perhaps, most wonderful of all is the 

 root's selective power, the ability to choose 

 from the various surrounding substances in 

 the soil those most congenial to its tastes. 

 Thus, of two plants grown side by side, the 

 one may absorb potash, the other phos- 

 phates ; and the one may elaborate a 

 nutritious food, whilst the other produces a 

 virulent poison. Hence arises the exhaus- 

 tion of soils, and the importance of a 

 scientific training to our farmers, that they 

 may comprehend the necessity of rotation 

 of crops and judicious manuring. An em- 

 phatic protest should be entered against the 

 wilful waste of the best of all fertilizers for 

 the impoverished land by the absurd — nay 

 wicked — disposal of the sewage of our towns. 

 As nothing in nature is absolutely lost, the 

 food taken from the soil ought sooner or 

 later, in some shape or form, to be restor- 

 ed to it again. Our plants and crops are 

 perishing for the lack of the very sub- 

 stances we are pouring into our rivers, 

 polluting our waters, contaminating our 

 air, poisoning our fish, and often our 

 fellow-men, whilst starving the poor farm- 

 ers ! From the rather startling statement 

 that the tip of the root may be called the 

 brain of the plant, it is not to be inferred 

 that there is claimed for it, sensory apparatus 

 and a set of nerves as complete as in the 

 higher animals. But numerous experiments 

 have proved that the extreme tip is not only 

 sensitive to contact with a hard substance 

 — or a corrosive, such as caustic — or common 

 grease, to which it has an excessive repug- 

 nance — but it is able to transmit the 

 sensation to an adjacent part, which then 

 bends away from the opposing object. Or if 

 it detects moisture on one side, it conveys 

 the impression to the mutable or bendable 

 part, which then turns towards the water. 

 If, after the inclination to turn in a given 

 direction has been transmitted to the root, 

 the extreme apex or sensitive part be cut off. 



the root will continue to bend in the 

 direction in which the impulse has been 

 given until a new apex has been rejuvenated, 

 when, if the obstruction has been removed, 

 the direction of growth will be resumed. To 

 find an analagous case in the animal world, 

 we must suppose an animal to have resolved 

 to raise or bend its body in a certain 

 direction, and when the movement has be- 

 gun its head is amputated, but the elevating 

 impulse conveyed to the body goes on for an 

 indefinite time. Recent research has proved 

 this general law to pervade all vegetable 

 existence, viz., that the apex of the growing 

 part of every plant — whether root, stem, 

 branch or leaf— -is in a constant state of 

 motion, continuously revolving or rotating 

 from side to side. The movement may be 

 slight, but it is decided enough to be appreci- 

 able. Being inherent in all plants, we see 

 that no special law is required to govern the 

 more obvious manifestations of it. The 

 same power which enables the infant root 

 in the germinating seed, to penetrate the 

 soil, aids the tender stem to break through 

 the ground, and we see it amplified and 

 modified, and not abrogated or superseded, 

 in the folding petals of the daisy, the exten- 

 sion and collapse of the sensitive plant, the 

 twining stem of the honeysuckle and the 

 hop, the clasping tendrils of the pea and 

 vine, and the adhesive suckers of the ivy and 

 Virginian creeper. The second part of the 

 lecture was chiefly occupied with a disser- 

 tation on the daisy, the singular structure of 

 its flowers, the lingering superstitions, curious 

 customs, and tender associations which 

 cluster around it. This was garnished and 

 embellished with numerous quotations from 

 the poets, who seem to be never weary of 

 singing the praises of this favourite flower. 

 The lecture was copiously illustrated by a 

 series of beautifully executed diagrams, 

 several interesting practical experiments, 

 and various specimens ; and it was attentive- 

 ly listened to by an appreciative audience. 



