MULTIPLIED ORGANIC P]FI'ECIS. 45 



evolution proceeds after this manner. For since it is now 

 known that no germ, animal or vegetable, contains the 

 slightest rudiment, trace, or indication of the future organ- 

 ism—now that the microscope has shown us that the first 

 process set up in every f(?rtih"zed germ, is a process of re- 

 peated spontaneons fissions ending in the production of a 

 mass of cells, not one of which exhibits any special charac- 

 ter : there seems no alternative but to suppose that the 

 partial organization at any moment subsisting in a growing 

 embryo, is transformed by the agencies acting upon it into 

 the succeeding phase of organization, and this into the 

 next, until, through ever-increasing complexities, the ulti- 

 mate form is reached. Thus, though the subtilty of the 

 forces and the slowness of the results^ prevent us from 

 directly showing that the stages of increasing heterogeneity 

 through which every embryo passes, severally arise from 

 the production of many changes by one force, yet, indi- 

 rectly^ we have strong evidence that they do so. 



We have marked iiow multitudinous are the effects 

 which one cause may generate in an adult organism ; that 

 a like multiplication of effects must happen in the unfold- 

 ing organism, we have observed in sundry illustrative 

 cases ; further, it has been pointed out that the ability 

 which like germs have to originate unlike forms, imphes that 

 the successive transformations result from the new chancres 

 superinduced on previous changes ; and we have seen that 

 structureless as every germ originally is, the development 

 of an organism out of it is otherwise incomprehensible. 

 Kot indeed that we can thus really explain the production 

 of any plant or animal. We are still in the dark respect- 

 ing those mysterious properties in virtue of which tlie 

 germ, when subject to fit influences, undergoes the special 

 changes that begin the series of transformations. All we 

 aim to show, is, that given a germ possessing these myste- 

 rious properties, the evolution of an organism from it. 



