i;o SCIENCE PROGRESS 



sediments now brought to the sea are from nine to fourteen times as great as those 

 of other geologic epochs. Past experience in matters geological teaches us to 

 regard with great suspicion theories that require a departure from the hypothesis 

 of practically uniform conditions. What Prof. Chamberlin's opinion may be is 

 known only to himself, but, in a recently published paper on the subject, he 

 assesses the lower Cambrian as, roughly, 75,000,000 years ago. 1 In any case, it 

 will be sufficient to point out that this argument is not available against Prof. 

 Sollas. Prof. Sollas's results refer to the maximum thickness of sedimentary 

 rock, and it is absurd to suppose that the fastest accumulation of sediment, 

 presumably representing the steepest land gradients, has, on that account, pro- 

 ceeded nine to fourteen times more slowly than under current conditions. The 

 average relief of the land has no bearing on the subject. Prof. Sollas's arguments 

 are valid as against any that Mr. Holmes has brought forward. As a matter of 

 fact, an attempt at a detailed refutation has been published, but Mr. Holmes 

 does not appear to be aware of it. 



With all the faults, however, there is some value in the publication of a book 

 on the subject by one specially competent to speak from the standpoint of radio- 

 activity, and we can echo his wish that the work will stimulate an interest in the 

 time problem, and provide material for further discussion. H. S. Shelton. 



Problems of Life and Reproduction. By Marcus Hartog, M.A, D.Sc, 

 F.L.S., F.R.H.S., Professor of Zoology in University College, Cork. 

 [Pp. xviii + 362.] (London : John Murray, 1913. Price 7s. 6d. net.) 



Dr. Hartog's book is, actually, a collection of essays published, from time to time, 

 in the leading scientific and popular journals. It is intelligible to those having no 

 special knowledge of the subject matter, admirably discursive, and yet possesses a 

 unity of its own. In such a work it is not easy to emphasise the salient points of 

 interest to the general reader. It may be regarded as the epitome of the biological 

 writings of a lifetime. The three features that stand out most prominently are, 

 perhaps, the pronounced neo-Lamarckian tendency, the Spencerian attitude 

 towards biological problems, and the appreciation of the biological writings of the 

 late Samuel Butler. All of these are of interest and value. Each one, separately, 

 would tend to give the writer a special position among English biologists, and all 

 three combined make his position distinctive and unique. Fashions in biological 

 theories change continually, and in every instance Dr. Hartog has the distinction 

 of maintaining the point of view that is not, at the present time, fashionable, and he 

 does so with a wealth of knowledge and a clearness of exposition that ensure him 

 a hearing both from biological specialists and from the general intelligent public. 



The first two features are, perhaps, but aspects of the same. No clearer or 

 more consistent statement of the so-called neo-Lamarckian view than Spencer's is 

 to be found in modern literature ; indeed, in its modern development, it might 

 more correctly be described as neo-Spencerian. Dr. Hartog is a worthy successor. 

 The uncritical and unphilosophical dogmatism of present-day neo-Darwinian 

 biologists, though masked, for the time being, by the rise of Mendelism, requires 

 a corrective, and Dr. Hartog admirably supplies the need. It is difficult, in a 

 brief review, to summarise or to criticise Dr. Hartog's arguments or to make 

 any original contribution to the discussion. The following extracts will illustrate 

 his point of view ; 



"We must consider what is the a priori ground that has led naturalists, 



1 Nature, vol. liii. p. 80. 



