MODERN PHILOSOPHICAL BIOLOGY. 713 



only an evolution of the individual from the moment when it became 

 more heterogeneous by the differentiation of parts and functions, but 

 also an evolution of the ensemble of living beings, from the first ap- 

 pearance of life in its least differentiated form up to the highest degree 

 of complexity in structure and function. 



If life is an evolution, of what is it an evolution ? If the question 

 refers to an individual of any given species, the answer is easily given, 

 for we can study the history of its life from the germinal cell to the 

 period of its full development, and to the end of its life. But if the 

 question refers to the ensemble of living Nature, only the middle por- 

 tion of which is known to us, and the beginning of which we have 

 no idea of save in imagination, then the reply must be only an hypothe- 

 sis. We find groups differing from one another by their respective 

 degrees of vital evolution, and we regard them as being, not as it 

 wei'e links of one chain, but rather the result of an evolution whicli 

 has taken different directions owing to different circumstances. 

 Hence we can admit only one starting-point, though the goals are 

 many. The divergent lines which we find in the development of the 

 forms of living things, in the history of life, warrant our supposing 

 the starting-point to be one, and at this point the evolution hyj^othesis 

 must jDlace the formation of primordial organic matter, whose reac- 

 tions with its environment present the first crude examines of vital 

 function. 



The hypothesis which accounts for the production of life by the 

 spontaneous generation of a complete organism from simple proto- 

 plasm is irreconcilable with evolution ; this woiald suppose something 

 more than an evolution, in fact a beginning in the absolute sense, 

 an enormous hiatus between the causes and their supposed effects. 

 But on the theory of evolution we can conceive of another mode of 

 formation. It is possible that even now, under existing cosmical 

 conditions, organic matter is produced; but it is more probable that 

 it was formed in an epoch when the cosmical forces now known 

 to us, especially heat and light, had on earth a greater intensity 

 than at present. The first types must have been more simple, less 

 definite, less fixed in form and structure, than the lowest rhizopods 

 of our day. Indeed, they must have been moi-e nearly allied to 

 protoplasm than even Haeckel's Protogenes / and, before evolution 

 could derive from these types our present infusoria, ages and ages 

 must have elapsed. Strictly speaking, we cannot call the first living 

 thing an organism at all, in the true sense of that term ; it is stretch- 

 ing the meaning of words to speak of types in connection with beings 

 whose form must have been perfectly unstable, and whose organization 

 had no structure. 



Of this quasi-organism we have merely a symbolic conception, 

 formed by combining two positive, empiric elements, viz., transforma- 

 tions of substances strictly evolutive, such as we see in the laboratory 



