CONGRUITY OF THE EVIDENCE 287 



is necessitated, in the medium in which it exists, by the nature 

 and properties of the complex organic molecules of which it is 

 composed. 



The fundamental difference between a crystal and an organism 

 lies, indeed, in the fact that the one is a ' statical ' and the other 

 a ' dynamical ' aggregate ; this difference being dependent upon 

 the great complexity of the molecules of which the latter is 

 composed. Organisms are dynamical aggregates because among 

 their molecules new motions and new arrangements are continually 

 being assumed ; in the course of which, in lower organisms, there 

 frequently arises a spontaneous division of the parent mass — that 

 is to say, ' fission ' or ' gemmation ' takes place. 



The intimate nature of the process of reproduction characterising 

 living things is revealed by a consideration of these processes of 

 ' fission ' and ' gemmation.' All parts of very low organisms, when 

 thus separated from the parent, have the power of developing into 

 living things of a similar kind. This property has points of 

 resemblance to the process whereby a fragment broken from a 

 pre-existing crystal, and thrown into a suitable solution, gradually 

 grows into a perfect crystal, similar to that from which it has been 

 derived. Though the fragment will reproduce a crystal similar 

 to that from which it was taken, the crystal can undergo no 

 spontaneous division. 



If it is true, as we affirm, that Torulae, and even Bacteria 

 (in aggregates if not singly) are able to develop into simple 

 forms of Fungi, and that such Bacteria and Torulas are merely 

 some of the primary forms most frequently assumed by certain 

 kinds of new-born living matter, then obviously the form and 

 structure of the Fungus would stand in the same relation to the 

 matter of which it is composed that the form and molecular 

 structure of the crystal does to its matter. There would be, 

 in fact, just as much reason why the new-born organism should 

 develop into the form of one already in existence, as there would 

 be that the crystal of sulphate of soda which forms to-day in a 

 solution of that substance, should resemble that which formed 

 under similar conditions twelve months or a hundred years 

 previously. He who believes in the uniformity of natural phe- 

 nomena could anticipate no other result. Living matter, which 

 we believe to be now produced de novo, speedily shapes itself 

 into some well-known form ; and so also new crystalline matter, 

 which may have been produced synthetically by the chemist 



