46 PRESENT-DAY RATIONALISM 



ridicules it ; but whatever nanie be proposed for it, there 

 is undoubtedly a " Directivity " in living beings of a kind 

 which is not observable in inorganic matter. It has also 

 been described as "Dominant". Each of these two 

 words expresses observable phenomena. 



Thus when a new variety of a plant or animal 

 appears, it is due to alterations in the structure, so that 

 the external visible organs appear different in some 

 degree from the corresponding organs of the parent. 

 The internal anatomy may undergo parallel changes. 

 That is to say, the tissues within are different ; and as 

 these tissues are made up of cells, which again arise 

 by divisions of nuclei, we arrive at the fundamental 

 sources of the changes of form ; and the conclusion is 

 expressed by saying that the protoplasm and nucleus 

 respond to the direct action of the environment, and at 

 once build up cells and tissues so as to make the organs 

 suitable, or in harmony with, the new conditions of life 

 supplied by the environment. Here, then, we have in- 

 ternal "Directivity" constantly displayed. 



The word " Dominant " might be used to represent 

 the " over-ruling " power of Life. 



And here it may be added that this innate power of 

 adaptation is as perceptible in microscopic fungi, as it is 

 in trees and herbs ; for there is, for example, a parasitic 

 fungus, Erysiphe graniinis, which attacks species of the 

 genus Bromns among grasses. The ob.server, Mr. E. S. 

 Salmon, F.L.S., remarks that specialisation has involved 

 the evolution of a considerable number of " biologic 

 forms" of the fungus, specially adapted to eight distinct 

 species o{ Bronius, respectively. 



Now supposing protoplasm were evolved from 

 minerals, there is much more to be accounted for and 

 explained than mere structure, such as all the enzymes 



