22 ON THE METHOD OF ZADIG i 



And if this be the case, the late advances which 

 have Ivrii iii.-i.lf in paloeontological discovery open 

 out a new field for such prophecies. For it lias 

 been ascertained with respect to many groups of 

 animals, that, as we trace them back in thai-, 

 their ancestors gradually cease to exhibit those 

 special modifications which at present characterise 

 the type, and more nearly embody the general plan 

 of the group to which they belong. 



Thus, in the well-known case of the horse, the 

 toes which are suppressed in the living horse are 

 found to be more and more complete in the older 

 members of the group, until, at the bottom of the 

 Tertiary series of America, we find an equine 

 animal which has four toes in front and three 

 behind. No remains of the horse tribe are at 

 present known from any Mesozoic deposit. Yet 

 who can doubt that, whenever a sufficiently extru- 

 sive series of lacustrine and fluviatile beds of tint 

 age becomes known, the lineage which has been 

 traced thus far will be continued by equine quad- 

 rupeds with an increasing number of digits, until 

 the horse type merges in the five-toed form 

 t\v;mls which these gradations point ? 



But the argument which holds good for the 

 hone, holds good, not only for all mammals, but 

 for the whole animal world. And as the study of 

 the pedigrees, or lines of evolution, to which, at 

 present, we have access, brings to light, as it 

 n redly will do, the laws of that process, we 



