CONCERNING PROTOPLASM. 77 



which make life ; and although the exact relationship of these forces 

 is as yet unknown, analogy leads us to believe that they are not 

 materially different, if they are different at all, from those which have 

 made the world of inorganic matter what it is. It is analogy, too, which 

 reminds us that certain forces produce, under combination, very 

 different results from those which they exert when acting in separate 

 array. The relationship and correlation of the physical forces not 

 merely teems with examples of such results, but leads us to think of 

 the possibility and probability that life remains a mystery to us simply 

 because the terms under which its component forces are combined 

 are as yet unknown. In any case, we require to postulate a " life- 

 force " of one kind or another. It remains for us to choose between 

 the " vital force " of former decades of biology a term committing 

 itself to no explanation of vital phenomena whatever and the idea 

 that in the properties of protoplasm derived whence and how we, 

 as yet, know not we find the true nature of life. 



But analogy rests not here. An extension of thoughts like the 

 foregoing leads us towards the world of inorganic matter with the 

 view of inquiring whether there exist any links or connections 

 between that lifeless universe and the living world which claims 

 protoplasm as its universal substratum. The forces which act upon 

 the lifeless world are those which also affect animals and plants ; 

 but the latter are enabled to resist, alter, and modify the action of 

 these forces in greater or less degree, whilst lifeless matter exists and 

 is acted upon without response. Otherwise, however, the phenomena 

 of the inorganic world, despite their sharp demarcation from the 

 phases of life, may be regarded as presenting us with many facts 

 of origin as inexplicable as those exhibited by living beings. It has 

 well been remarked that the growth of the crystal, taking place in 

 virtue of physical laws, to attain an exact and unvarying form, is as 

 mysterious as the growth of the tree ; and that common salt should 

 crystallise in the form of the cube is as profound a mystery as 

 that an acorn should become an oak, or another protoplasmic germ 

 evolve the human form. If we are to assume that the forces 

 which rule the world of life are inexplicable simply because they are 

 living forces, it might equally well be maintained that the inorganic 

 world and its ways should be the subjects of similar mysticism. Far 

 more rational, because more likely to be true, are the ideas which lead 

 us to note in the living world the highest term to which matter may 

 attain. As the living world is dependent on the non-living for its 

 support, as we are both in the earth and of the earth, so may we 

 conceive that the forces which mould the world, which disperse the 

 waters and rule the clouds, have contributed in their highest mani- 

 festations to combine matter into its most subtle combinations in the 

 form of the animal and in the guise of the plant. Huxley's words 



