THE INNER LIFE OF PLANTS 317 



tute of the proverbial exceptions, that every phase of recent research 

 in botany has but served to show us that the world of plant-life is 

 not merely a universe of activity, but that it has even its own analogies, 

 in the way of likes and dislikes and of mental phenomena, to the 

 phases we see in the animal world, and, indeed, in ourselves. 



One of the most interesting of those aspects of plants, in which 

 they may be regarded as approaching the animal world in their con- 

 stitution, relates to the marked influence of what may legitimately be 

 named habit. That the animal frame should present itself as the seat 

 of definite actions which become perpetuated and repeated in the indi- 

 vidual history, until they become part and parcel of the constitution of 

 the race, is, of course, tacitly admitted to be a common and familiar 

 feature of the animal constitution. It may in the same way be 

 shown that in plants the influence of " habit " is as powerfully exhi- 

 bited as in the neighbour-kingdom. For instance, in the earliest 

 phases of plant-growth, the influence of habit as affecting that growth 

 and development may be plainly observed. When the structure of 

 an ordinary seed, such as that of a pea or bean, is investigated, it 

 is found to consist of certain coverings, of two bodies called cotyle- 

 dons or " seed-leaves," of a young root or radicle, and of a youthful 

 stem, the plumule of the botanist. The two latter parts, in fact, 

 form the young plant. Through their development, the plant will 

 ultimately appear in all the fulness of growth and perfection. Now, 

 when such a seed germinates, the radicle, or young root, is the first 

 structure to break through the coverings of the seed, being followed 

 in due course by the youthful stem. It constitutes a remarkable and 

 at the same time interesting feature of plant-habit, to discover that 

 whatever the position of the seed, the young root invariably seeks 

 the ground, whilst the stem as invariably avoids the ground and seeks 

 the light. If, for example, the root on emerging from the seed should 

 point upwards, it will gradually curve as it grows, so as to enter the 

 ground ; whilst the young stem in such a case, placed at first in the 

 position of the root, will, in its turn, adjust itself to the exigency 

 of its position and curve itself so as to grow upwards. Associated 

 with the tendency or habit on the part of the young root and stem 

 of growing each in its proper direction, we discover certain peculiar 

 structural conditions. That the growing parts of the plant are in- 

 fluenced by gravitation is, of course, unquestionable. It has been 

 ascertained that if a growing stem and root are laid horizontally, the 

 stem will bend so as to render its upper side concave and its under 

 surface convex. Thus its extremity comes to grow upwards ; but in 

 the root the reverse action takes place, and the under side becoming 

 concave whilst the upper surface is convex, causes the root-tip to 

 seek the ground. The influence thus exerted by gravity on the 

 growing parts of plants is termed " Geotropism ; " and it may readily 



