THE BEGINNINGS OF LIFE. 593 



intrinsic properties of the more or less similar matter 

 from which they have been derived, have also more to do 

 with their forms and structures than any differences in 

 the conditions under which they have been born. And 

 yet we find that many of such lower organisms are quite 

 unable to adjust themselves to slight changes in their 

 ^ conditions of life.' When these oveitake them, they 

 either die or become converted into new forms — lower or 

 higher as the case may be^ And whether any particular 

 change of conditions can or can not produce direct 

 effects upon an organism, seems to depend princi- 

 pally upon the nature of the organism itself. This 

 is undoubtedly the case with crystals; and since it 

 appears also to hold good for organisms, it ought to 

 impress us with a conviction of the immense importance 

 of the aggregate polarities of the organism and of the 

 exact nature of the complex moving equilibrium which 

 exists in each case, in reference to the possible influence 

 cf any particular change in external conditions. 



Although, therefore, Mr. Darwin does not believe 



^ Thus it would appear that an essential similarity exists amongst 

 the forms encountered in different regions (^Pritchard's ' Infusoiia,' p. 375), 

 because the elementary forms of vegetal matter (from which so many of 

 the Infusoria and Cryptogams are derived) have an essentially similar 

 nature in these various regions (see p. 613). The several forms unfold, 

 therefore, more or less immediately into such and such organisms, 

 according to the molecular composition of the matrices from which 

 they start. But if new influences impinge upon such impressionable 

 organisms, they, for the most part, either die, or else the matter of which 

 they are composed undergoes some marked htterogenetic transforma, 

 tion, by which higher or lower organisms may be produced. 

 VOL. II. Q q 



