APPENDIX A

(Page 5)

THERE is also a mode of existence which is termed life, which exhibits neither change, activity, nor sensitiveness. Seeds may be kept for long periods without germinating, and yet retain their vitality; animalsthe Tardigrada, Rotifers, Anguillulidæ have been revived after having been shrivelled up for years; frogs, worms and fishes have often been thawed alive out of hard ice. All these are said to possess life. But here we must distinguish between actual and latent or potential life. In this latter sense only can seeds, dried up or frozen animals, be said to possess life. There is all the difference between actual and potential life, as there is between a reservoir actually supplying motive power, and another reservoir which may be capable of supplying it, provided the proper connections were made for bringing it into use. The term Susceptibility might properly designate life in the latter sense. Potential life is, however, in reality, not life at all, any more than a steam engine is a power without the actuating steam.

APPENDIX B

(Page 23)

KERNER and Oliver thus describe the movements of the contents of a plant cell :-"These movements may be observed very clearly under the microscope in the case of large cells with thin and very transparent cell membranes, especially when the colourless, translucent and gelatinous substance of the protoplasm—not always sharply defined in contour-happen to be studded with minute dark granules; the so-called microsomata. These granules are driven backwards and forwards with the stream, like particles of mud in turbid water, and their motion reveals that of the protoplasm, wherein they are embedded. Seeing particles gliding in all directions through the cell cavity, arranged irregularly in chains, rows and clusters in the protoplasmic strands, we are justified in concluding that this motion takes place in the substance of the strands itself. The movement, moreover, is not confined to isolated strands, but occurs in all. Granular currents flow hither and hither, now uniting, now again dividing. They often run in opposite directions, even when only a trifling distance apart; sometimes two chains are drifted in this way, when actually close

together in the same band of protoplasm. The streams pour along the primordial utricle, and whilst there divide into a number of arms, meeting and stemming one another and forming little eddies; then they are gathered together again and turn into another strand. of the more central protoplasm. The individual granules in the currents are seen to move with unequal rapidity, according to their sizes; the smaller particles progress faster than the larger, and the larger are often overtaken by the less, and when this happens the result often is that the centre stream stops. If so, however, the crowded particles are suddenly rolled forward again at a swifter pace, like bits of stone in the bed of a river, as it passes from a level valley into a gorge. The course of the streaming protoplasm remains throughout sharply marked off from the watery sap in the vacuoles, and none of the granules ever pass over into the cell sap from the protoplasm. Larger bodies, such as the round grains of green colouring matter or chlorophyll, are in many instances not carried forward, but remain stationary, the protoplasmic stream gliding over them without altering them in any way. Further, the outermost layer of the protoplast, contiguous with the cell membrane, is not in visible motion in most vegetable cells. On the other hand, occasionally the entire protoplast undoubtedly acquires a movement of rotation, and then the larger bodies embedded in its substance, i.e. chlorophyll corpuscles, are driven along like driftwood in a mountain torrent. On these occasions a wonderful circulation and undulation of the entire mass takes place; chlorophyll grains are whirled along one after the other at varying speeds, as if trying to overtake one another; and yet

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another structure, the cell-nucleus, presently to be discussed, is dragged along, being unable to withstand the pressure, and following the various displacements of the network of protoplasmic strands, in which it is involved, is at one moment pulled alongside of the cell wall, at another again is taken in tow by a rope of central protoplasm and hauled transversely across the interior of the cell."

APPENDIX C

(Page 38)

SIR Michael Foster, referring to this experiment, says: "This at first sight looks like an intelligent choice . but a frog deprived of its brain, so that the spinal cord only is left, makes no spontaneous movement at all. Such an entire absence of spontaneity is wholly inconsistent with intelligence. We are, therefore, left to conclude that the phenomena must be explained in some other way than by being referred to the working of intelligence."-Text Book of Physiology, part iii. p. 909.

Haeckel similarly disposes of the facts by remarking that "we only admit the presence of consciousness in man and in the higher animals.”—Riddle of the Universe, p. 118.

Wundt, on the other hand, interprets the phenomena. in another fashion. "The decapitated frog," he remarks," moves its leg against the pincers with which it is irritated, or wipes away with its foot the drop of acid applied to its skin. It sometimes tries to withdraw from a mechanical or electrical irritation by a leap. When brought into an unusual position, e.g. placed on its back, it perhaps returns to its previous posture. Here, then, the stimulus does not introduce merely a movement in general which spreads from the