Bakewell. — Is Life a Distinct Force? 411 



With the other qualities of living matter I shall not at present deal ; 

 these three are essential to any form of living matter, and are found in all, 

 from the humblest of the Protista up to man. 



Life then I should define to be, — that force or combination of forces 

 which gives to protoplasm its power of motion, of self-nutrition, and of 

 reproduction. In this definition it will be observed that I avoid assuming 

 that life is a force — it may be the result of a combination of forces. 



Life is either somatic or molecular. In the simplest forms of living 

 beings, the somatic and molecular life are inseparable, as the individual 

 consists but of a single cell. If you kill an Amoeba, for example, you 

 destroy both the somatic and molecular life at the same time. But except 

 the simplest organisms, whether vegetal or animal, living beings are built 

 up of corpuscles, sometimes in the form of cells, sometimes in more com- 

 plex tissues formed originally out of cells, each endowed with life, which is 

 to a certain limited extent independent of the life of the whole organism. 

 This is what is called molecular life. The life of the organism as a whole 

 is called somatic life. It is possible in many of these organisms, particu- 

 larly in what are called the higher or more complex ones, for somatic life to 

 cease long before the individual molecules of which the being is built up 

 have lost their vital properties. 



Living protoplasm, as I have before said, is an albuminoid substance. 

 It consists of carbon, oxygen, hydrogen, and a little phosphorus and 

 sulphur. 



On Motion as a quality of Living Matter. — It is admitted by every one 

 that non-living matter, in whatever form it may be found, cannot move of 

 itself, nor unless acted on by some external force. But living protoplasm, 

 as long as life exists, is endowed with motion. A simple cell like the 

 Amoeba (I use the word cell for convenience — the Amoeba is not properly a 

 cell) or a leucocyte, and many of the simpler forms of vegetal and animal 

 life can be seen to move about in the medium in which they exist. But the 

 higher forms of vegetal life, it may be thought, do not move unless acted on 

 by some external force. A lichen seems to cling to the rock on which it 

 has fixed itself; and even those plants like the sensitive plant, or the 

 sundew, or Venus's fly-trap, which are known to move and grasp objects 

 brought into contact with them, may be thought not to move spontaneously, 

 or without being acted upon from without. This appearance of inertia is 

 however fallacious, for whether you examine the lichen or the forest tree 

 that has been rooted to its native earth for a thousand years, you will find 

 that in every part of its structure change is going on — fluids are circulating ; 

 vessels and ducts and fibres are being produced, removed, and renewed ; 

 the reproductive process is going on ; water is being absorbed or given off ; 



