SPECIES. 127 



time to our eyes here and there a certain number of species, 

 inferior in organisation to those in the most ancient rocks. 



As to explaining how a part of the ancient species has been 

 able to modify itself whilst another has remained stationary, 

 we must admit that all these influences of medium have always 

 been exclusively local, so that all the coexisting vertebrata have 

 never been able to submit at once to its influence. We must 

 understand by medium, the whole of the circumstances, past 

 or present, which are able to influence organism mediately or 

 immediately in any manner whatsoever. The ancestors of an 

 animal, as well as the sun which warms it, and the parasites 

 which devour it, make up a part of this medium. 



But if it is easy to explain variety by the medium, it is a 

 difficulty against which the mind struggles. How can we 

 explain ascending and progressive variety ? must we believe 

 in some finality, an end settled beforehand ? We do not think 

 so. Finality is a sort of divine prevision, and the world as 

 regards this hypothesis is still in tutelage ; we would rather 

 believe in a creating intelligence. A simple example will make 

 our meaning understood. In the vegetable world this strikes 

 us forcibly : the most simply formed plants are precisely 

 those which approach most nearly to animals by reason of 

 their physiological manifestations.* The plants which they 

 call superior, by placing them in an organographic point of 

 view, are in reality inferior, so that these plants are simple in 

 reference to the dicotyledons which have necessarily succeeded 

 them, and there has been in reality a retrograde march of life, 

 instead of the ascending march of the animal kingdom. Must 

 we seek for the reason of this difference in the presence of a 

 nervous system ? We think so. We then would admit that 

 organism would tend to modify itself by an inconscient act of 

 the will, analogous to those which rule most physiological 

 actions; this would be something like the possible increase 

 or growth of the head by reason of the influence of civilisation 

 of which we have before spoken, f And whilst all the specific 



* Predominance of the immediate azotic principles, respiration comparable 

 to that of animals, voluntary movements, indivisibility of organism, etc. 

 f [See above, pp. 46, 47. EDITOR.] 



