CONGEUITY OF THE EVIDENCE 299 



Heterogenesis. Let us see, therefore, which view is most in 

 accordance with certain well-known and generally admitted classes 

 of facts, and which view is more or less completely opposed 

 thereto, for as Herbert Spencer has said, "There is no mode of 

 establishing the validity of any belief except that of showing its 

 entire congruity with all other beliefs." 



The first of these classes of facts, which may be regarded as a 

 kind of touchstone for testing the relative validity of the two views, 

 is the present day existence of vast multitudes of lowest organisms of all 

 kinds. If all the forms of life that have ever existed upon the 

 surface of the earth have been derived from the primordial forms 

 which took origin by natural synthetic processes occurring only in 

 an incalculably remote past, no adequate and consistent explanation 

 would be forthcoming of the undoubted existence, at the present 

 day, of the teeming multitudes of such lower organisms as have 

 been above referred to. For if the assumed gradual development 

 of higher forms of life, during all past geologic ages, has been 

 largely due to the intrinsic mutabihty of living matter, as the 

 Evolution hypothesis assumes, would it not be a stultification of 

 that hypothesis to suppose that such primordial forms as Bacteria, 

 Torulse, Monads, Amcebse, and Ciliated Infusoria have remained 

 practically unchanged, and in these low grades, for untold millions 

 of years ? Yet those whose views are at present most widely 

 accepted would have us believe that ages and ages before the 

 advent of Man or his immediate predecessors upon the earth, the 

 ancestry of the Bacterium, the Amceba, the Monad, the Mould, or 

 of any of the low infusorial animalcules now to be seen in their 

 respective habitats, had been tenants of our globe. The mere 

 suggestion seems to carry absurdity on its face. If this were really 

 so, then we could only expect that such forms would be the very 

 types of conservatism and stability ; whereas, as a matter of fact, all 



Diatoms from cells of Chlorochytrium in dead Duckweed ; the origin of pigment 

 Amoebae in Vaucheria filaments or ' resting spores,' or some of the remarkable 

 changes which I have described as occurring within the cells of Nitella. Some 

 of these transformations can generally be induced or found almost at will. 

 Others, as I have shown, are much more fitful in their occurrence, or can only be 

 met with under conditions not always easy to realise, as with the transformation 

 of Hydatina eggs into Ciliated Infusoria, and many other of the changes which I 

 have recorded. This latter difficulty may be due sometimes to dearth of the 

 proper organisms ; sometimes to unknown changes in the intimate nature of the 

 organisms not favourable to transformations previously seen — just as de Vries 

 has found in regard to the occurrence of 'mutations,' at different times or in 

 different species. 



