THE BEGINNINGS OF LIFE. 105 



through changes in those conditions which are fatal 

 to beings of higher structure and more specialized 

 constitution; whilst, on the other, they undergo such 

 modifications under the influence of those changes as 

 may produce a very wide departure from the original 

 type/ These views now seem somewhat inconsistent 

 and contradictory. Extreme variability is predicated 

 on the one hand, and yet extreme stability is affirmed to 

 have been displayed through long geologic ages. Doubt- 

 less, the ^ conditions ' obtaining at the bottom of deep 

 oceans in past times may not have been very different 

 from what they are at present ^ ; but such uniformity of 

 conditions could not entail the long-continued pre- 

 servation of the same simple structural types, unless 

 we suppose that all internal causes of change in the 

 organisms themselves had ceased to exist. And yet 

 the continuous existence of internal causes of change 

 is, in reality, the essential attribute of living matter, 

 which could no more have been absent from Forami- 

 nifera during all these ages of apparent non-development, 

 than it is absent at the present day in the ever-varying 

 Fungi, Alg^, and Lichens, which astonish us by their 

 rapid and protean changes of form. It is certain, 

 moreover, that those who believe exclusively in the 



^ If certain lower organisms, therefore, developed into Foraminifera 

 in remote geologic ages, there is no reason why they should not develop 

 in the present day into essentially similar forms ; and variation may 

 now tend to manifest itself in the same fashion as it did formerly, o'wang 

 to the fact that the causes (both intrinsic and extrinsic) leading to this 

 variation are essentially similar. 



