REVIEWS 671 



scovodonia in the vegetation of a shingle beach gives quite a wrong impression 

 of its characteristic flora. 



In the general conception there is much to be commended, as, for instance, 

 the inclusion of sections deahng with the soil, and the origin of the British 

 flora; but in the execution there is much to be desired. 



E. J.S. 



Symbiosis. A Socio-Physiological Study of Evolution. By H. Reinheimer. 

 (Pp. xii. + 295.) (London : Headley Brothers, 1920.) 



Mr. Reinheimer's work is frankly unorthodox, both in subject and treatment, 

 and therefore in evaluating the thesis which he presents one must be careful 

 to avoid prejudice, due to a not unnatural irritation at his methods of pre- 

 sentation. 



The value of such works mainly depends on the fresh view-point from 

 which ascertained facts are considered, but is necessarily determined by their 

 proper and complete comprehension. 



The title itself is somewhat misleading since the term Symbiosis is given a 

 much wider meaning beyond relations involving organic connection. 



The author presents us with a biological philosophy based on the assump- 

 tion that success in the evolutionary process is dependent on the measure of 

 the organism's contribution to the biological community as a whole. There 

 is much that might be advanced in support of certain aspects of this view, 

 and in so far as the author lays stress on the reciprocal relations of organisms, 

 the warp and woof of the organic world which is so frequently overlooked, we 

 are at one with him. When, however, we come to the basis of Mr. Rein- 

 heimer's hypothesis it resolves itself into a question of the superiority, if any, 

 of Cystococcus symbiotic, over Cystococcus growing freely. 



When we turn to the evidence adduced we find that the facts are often 

 only partially apprehended. For example, though it is apparently true of the 

 great majority of species that cross-fertilisation is beneficial, and often essen- 

 tial, the fact is ignored that there is a minority, for which self-fertilisation 

 is equally necessary, whilst some of the most successful species and genera at 

 the present day are even apogamous. Again, the statement that " Mendelism 

 has shown that under domestication factor after factor is lost," is no argu- 

 ment for the ill efiects of cultivation since wild races, equally, show variations 

 of the same type as those here referred to. 



The view that predatory animals or plants are more subject to parasitism 

 than others will scarcely bear a moment's investigation, whilst it is an equal 

 perversion of the facts to state that all plants whose pollen causes hay-fever 

 are useless weeds. 



It is largely on such half-truths, with their pernicious verisimilitude, that 

 facile generalisations are based, which the author claims are thereby well 



substantiated. 



E. J. Salisbury. 



An Introduction to the Structure and Reproduction of Plants. By F. E. 



Fritch, D.Sc, Ph.D., F.L.S., Professor of Botany, East London College, 

 University of London, and E. J. Salisbury, D.Sc, F.L.S., Lecturer 

 in Botany and Fellow of University College, University of London. 

 [Pp. viii + 458, with 230 figures and illustrations.] (London: 

 G. Bell & Sons, 1920. Price 15s. net.) 



This volume is a sequel to the authors' well-known Introduction to the Study 

 of Plants. The latter work did not treat of the minute structure of plants 

 nor of the details of their life-history. The book before us may be considered 

 supplementary in that it treats more particularly of these aspects of the 

 subject. It is divided into two parts, " The Anatomy of Plants " and " The 



