NOTICES OF NEW BOOKS. 235 



Bleak, Eoach, and small fry have appeared in all the reaches, 

 from Putney upwards ; while Smelts now ascend the Thames as 

 they did before the river was polluted, and are freely caught at 

 Chiswick. We may also hope for the plentiful appearance once 

 more of the Crayfish, whose almost complete destruction was due 

 to a disease, well known in France, which first appeared near 

 Staines, and worked its way up the Thames. 



We have heartily enjoyed the perusal of this nicely illustrated 

 book, and trust that it may be the harbinger of other work on 

 the natural history of our well-loved river. 



A Treatise on the Birds of Gloucestershire, ivith a Reference List 

 of all the Species known to have appeared in the County. 

 By W. L. Mellersh, M.A. Gloucester : John Bellows. 

 London : R. H. Porter. 



Compared with most books on county ornithology, this pub- 

 lication is distinctly novel, and written on a different method ; 

 the presence or absence of birds in Gloucestershire is discussed 

 more on a philosophical than on a reporter's basis ; the geological 

 floor, with its consequent surface flora, is shown to have its in- 

 fluence in the distribution of our avifauna, and we at length feel 

 that there is some reason for the presence of the rare bird that 

 fell to the gun of the faithful recorder. Gloucestershire is thus 

 considered as a dominant partner, and the presence of birds less 

 of a chance occurrence. We are not attempting to spoil a good 

 book by absurd panegyric, but we do recognize that Mr. Mellersh 

 has proposed a philosophical basis for a recognition of even the 

 birds of a single county. To find there is a reason to be adduced 

 on natural causation for the presence of a bird is tantamount to 

 our believing in a purpose running through the ages. We know 

 that causation is often confused with theory by many writers, 

 but the still small voice is yet recognized in biology, despite the 

 discrepancies in rival suggestions. In fact, evolution is slowly 

 becoming an orthodox idea in contradistinction to the theories of 

 specialists and doctrinaires. Science is more concerned with 

 the reason why a bird is in a certain habitat, rather than with the 

 fact that it is there ; and that is a question that the author of 

 this book shows is capable of discussion. His enumeration may 



