xxvi THE BEGINNINGS OF LIFE. 



evolution of organisms, there is every reason for believing 

 that cavities occur or are formed within crystals of ammonic 

 tartrate l , and also (as I have just attempted to show) that 

 the confervoid-looking filaments and the fungus-spores have 

 undergone a process of growth and development within such 

 cavities. But if ' the conditions ' are favourable enough to 

 permit, or even to stimulate, the molecular activity of certain 

 living particles ; and if such molecular activity, whereby the 

 living specks grow and develop, is but the modified mani- 

 festation of incident physical forces, I see no theoretical 

 reason why the self-same physical forces acting upon the 

 self- same materials should not have been able, in the 

 same place, to initiate a molecular collocation similar to 

 that which they now help to build up from moment to 

 moment. We have been, perhaps, only too much in the 

 habit of looking upon this as impossible. But ignoring, as 

 far as we can, this habit of mind for the moment, let us look 

 at the facts as they are. Will it be at all easier for those who 

 believe in no special 'vital principle,' to understand how 

 from moment to moment not-living matter is converted into 

 matter which lives ? This process is continually taking place 

 in all growing representatives of the vegetable kingdom, but 

 no one ever thinks of doubting its occurrence merely because 

 he is unable to understand how it takes place. If it is 

 conceded that a de novo evolution of specks of living matter 

 is possible, then, I think, most physiologists will at once 

 admit, that where specks of living matter are able to grow 



1 The gases which appear in bubbles increase in quantity with the 

 age of the crystal, and they have been seen lodging in cavities 

 within the crystal. These cavities are, perhaps, more especially liable 

 to form in those crystals which are not perfect in shape, and which pre- 

 sent a more or less opaque appearance in their interior. Such less 

 perfect types are possibly, on account of this defective form, more prone 

 to undergo molecular changes under the influence of incident forces, 

 especially in the neighbourhood of and around some fibre-fragment 

 which has been enclosed. 



