102 REPORT— 1873. 



With all our admiration, however, for the doctrine of Evolution, as one of the 

 most fertile and comprehensive of philosophic hypotheses, we cannot shut our eyes 

 to the difficulties which lie in the way of accepting it to the full extent which has 

 been sometimes claimed for it. It must be borne in mind that though among 

 some of the higher Vertebrata we can trace back for some distance in geological 

 time a continuous series of forms which may safely be regarded as derived from 

 one another by gradual modification (as has been done, for example, so success- 

 fully by Prof. Pluxley in the case of the Horse), yet the instances are very few in 

 which such a sequence has been actually established ; while the first appearance 

 on the earth's crust of the various classes presents itself in forms which by no 

 means belong to the lowest or most generalized of their living representatives. On 

 this fact, however, I do not lay much stress ; for it will admit of explanation by 

 referring it to the deficiency of the geological record, and then demanding a lapse 

 of time (of enormous length, it is true) diuing which the necessary modifications 

 would be in progress before the earliest phase of which we have any knowledge 

 could have been reached. 



Again, we must not lose sight of the hypothetical nature of those primordial 

 forms in which we regard the branches of our genealogical tree as taking their 

 origin ; and while the doctrine of the recapitulation of ancestral forms has much 

 probability, and harmonizes with the other aspects of the Evolution doctrine into 

 a beautifully symmetrical system, it is one for which a sufficient number of actually 

 observed facts have not yet been adduced to remove it altogether from the region 

 of hypothesis. 



Even the case of the Graptolites already adduced is an illustration rather than a 

 proof; for the difficulty of determining the true nature of such obscure fossils is so 

 great, that we may be altogether mistaken in our views of their structure and 

 affinities. 



To me, however, one of the chief difficulties in the way of the doctrine of evolu- 

 tion, when carried to the extreme length for which some of its advocates contend, 

 appears to be the unbroken continuity of inherited life which it necessarily requires 

 through a period of time whose vastness is such that the mind of man is utterly 

 incapable of comprehending it. Vast periods, it is true, are necessary in order to 

 render the phenomena of evolution possible ; but the vastness which the antiquity 

 of life, as shown by its remains in the oldest fossiliferous strata, requires lis to give 

 to these periods may be even greater than is compatible with continuity. 



We have no reason to suppose that the reproductive faculty in organized beings 

 is endowed with unlimited power of extension ; and yet, to go no further back than 

 the SUm-ian period (though the seas which bore the Eozoon were probably as far 

 anterior to those of the Silurian as these are anterior to our own), the hypothesis of 

 evolution, when carried to the extreme length of which it seems susceptible, 

 requires that in that same Silurian period the ancestors of the present living forms 

 must have existed, and that their life had continued by inheritance through all the 

 ramifications of a single genealogical tree down to our own time — the bi'anches of 

 the tree, it is true, here and there falling away, with the extinction of whole genera 

 and families and tribes, but stUl some always remaining to carry on the life of the 

 base through a period of time to all intents and purposes infinite. It is ti'ue that 

 in a few cases a continuous series of forms, regularly passing from lower to higher 

 degrees of specialization, and very probably connected with one another by direct 

 descent, may be followed through long geological periods — as, for example, the gra- 

 duated series, already alluded to, which may be traced between certain mammals of 

 the Eocene and others living in our own time, as well as the very low forms which 

 have come down to us, apparently unmodified, from the epoch of tlie Chalk ; but 

 incalculably gi-eat as are these periods, they are but as the swing of the pendulum 

 in a millennium, when compared with the time which has elapsed since the first 

 animalization of our globe. 



Is the faculty of reproduction so wonderfully tenacious as all this, that through 

 periods of inconceivable dm'ation, and exposed to influences the most intense and 

 the most varied, it has still come down to us in an unbroken stream ? Have the 

 strongest, which had survived in the struggle for existence, necessarily lianded 

 down to the strongest which shoidd follow them the power of continuing, as a per- 



