A LIVING MYSTERY. 



•35 



have noticed how the common stone-crops will grow and root from 

 any little scrap or fragment or bit that falls by accident upon 

 damp soil. If we go down to the very bottom of the matter, it is 

 clear that the plant tends to reproduce itself, whole and complete, 

 from every part of itself — tends to increase in its own shape, and 

 repeat itself anew in fresh leaves and branches. Why is this ? 

 "Well, such a tendency results necessarily from the fundamental 

 principle of cell-growth. Every living vegetable cell containing 

 chlorophyl is always producing within itself fresh vital matter 

 of its OAvn kind ; and this vital matter, at last outgrowing the ca- 

 pacity of the mother-cell, pushes itself out through the cell-wall, 

 and grows into a new cell like the one it left. And it does so in 

 the very last resort in virtue of that curious chemical property of 

 the stuff we call chlorophyl, whereby such chlorophyl, under the 

 influence of sunlight, sejDarates the carbon and oxygen of car- 

 bonic acid, and builds them up once more into living matter of 

 the particular sort composing the plant in which it exists. 



Given a chemical body which can so increase the sum-total of 

 living matter, and there must needs result the phenomenon of 

 growth. Living matter is always being made anew from the 

 non-living. But observe that in each plant the material thus as- 

 similated from the air (or rather the carbonic acid floating in it), 

 and more remotely from the earth and water, is built up into the 

 forms of the particular plant itself — becomes distinctively, not 

 mere living matter in the abstract, but strawberry matter, or 

 stone-crop matter, or cactus matter, or whatever else the indi- 

 vidual plant may happen to be. In this we get the real secret of 

 like reproducing like. It results as a corollary from the principle 

 of assimilation. Most people see a mystery in the particular fact 

 that offspring resemble parents, but they see no mystery in the 

 general fact that the parent reproduces or renews the parts of 

 itself from alien material. In reality, the final explanation lies 

 on this deeper and more essential level. It is just as strange that 

 a rose should put out fresh leaves and shoots as that its seed 

 should grow up into a fresh rose-bush. 



The true exj^lanation seems to be, as Mr. Herbert Spencer long 

 ago suggested, that each organism has an inherent physical tend- 

 ency (of the nature of polarity) to complete its own organic form, 

 in somewhat the same way as a broken crystal, placed in a solu- 

 tion of its own material, has a tendency to replace its lost por- 

 tions. The organic type, in other words, resembles the crystalline 

 in this — that the material of which it is composed, when left to 

 its own internal forces, tends, under the free play of those forces 

 alone, to arrange itself in a certain definite specific shape. 



In time, however, every organism or colony of organisms 

 seems to lose this primitive plastic power of producing fresh 



