XII] OF THE FORAMINIFERA 873 



difference between the "explanations" of the physicist and those 

 of the biologist. 



In the order of physical and mathematical complexity there is 

 no question of the sequence of historic time. The forces that bring 

 about the sphere, the cylinder or the ellipsoid are the same yesterday 

 and to-morrow. A snow-crystal is the same to-day as when the first 

 snows fell. The physical forces which mould the forms of Orbulina, 

 of Astrorhiza, of Lagena or of Nodosaria to-day were still the same, 

 and for aught we have reason to believe the physical conditions 

 under which they worked were not appreciably different, in that 

 yesterday which we call the Cretaceous epoch; or, for aught we 

 know, throughout all that duration of time which is marked, but 

 not measured, by the geological record. 



In a word, the minuteness of our organism brings its conformation 

 as a whole within the range of the molecular forces; the laws of 

 its growth and form appear to lie on simple lines; what Bergson 

 calls* the "ideal kinship" is plain and certain, but the "material 

 afiihation" is problematic and obscure; and, in the end and upshot, 

 it seems to me by no means certain that the biologist's usual mode 

 of reasoning is appropriate to the case, or that the concept of con- 

 tinuous historical evolution must necessarily, or may safely and 

 legitimately, be employed. 



That things not only alter but improve is an article of faith, and 

 the boldest of evolutionary conceptions. How far it be true -were 

 very hard to say; but I for one imagine that a pterodactyl flew no 

 less w^ell than does an albatross, and that Old Red Sandstone fishes 

 swam as well and easily as the fishes of our own seas. 



* The evolutionist theory, as Bergson puts it, "consists above all in establishing 

 relations of ideal kinship, and in maintaining that wherever there is this relation of, 

 so to speak, logical affiliation between forms, there is also a relation of chronological 

 succession between the species in which these forms are materialised''^ {Creative 

 Evolution, 1911, p. 26). Cf. supra, p. 412. 



