NOTICES OF BOOKS. 223 



by tlie extinction or dying-out of the intermediate forms — and 

 therefore by an accidental occurrence — be correct, then of course 

 there would be nothing to object to in their proceedings as regards 

 the exclusion of intermediate forms from a series of graduated 

 transitions between two species, which would not then be sharply 

 defined on either side ; for if the intermediate forms of the species 

 now isolated had not died out, they would have to be included with 

 the others in the same girdle ; and if, for example, all the forms 

 which have ever originated in the genus Hieracium were still in 

 existence, the distinction of species generally would be nothing 

 more than an arbitrary cutting-up of the network of forms into 

 approximately equal-sized portions. At least the views of the 

 authors tend to this conclusion ; for they see in those minute 

 variations, as they occur so multifariously in the Hieracia especially, 

 the beginnings of species-formation, and believe that these have 

 always commenced with small steps of the kind, and that existent 

 gaps in the series are explicable simply by the dying-out process. 



We are well aware that these views — also entertained by Darwin 

 — are prevalent among the majority of enquirers ; nevertheless we 

 would remind them that they are, after all, mere speculations to 

 which facts cannot always be tacked on without force. Experience 

 indicates rather that species-formation is not always consequent 

 upon small gradations, but that at all times and perhaps in certain 

 seasons more rapid transformations have taken place ; so that we 

 might even, with 0. Heer, speak of a species mctutnorphosis. In 

 this light the gaps between the isolated species would acquire a 

 higher significance, and one could no longer consider these frag- 

 ments of a closely woven circle of forms originating in very small 

 steps of variation as their equivalents in value. Want of sjiace un- 

 fortunately prevents us from going deeper into these matters, besides 

 which such purely theoretical notions have no bearing upon the 

 practical value of the book under consideration. As regards the 

 form of it, it may seem rather strange that Latin, sometimes by 

 itself and sometimes together with German, is used for the diagnoses 

 of the species and of the groups, while for the subspecies and 

 varieties only German is employed. We think the adoption of one 

 language would have been more appropriate. The book is admirably 

 got up. 



New Books. — A. Jansen, 'Jean Jacques Eousseau als Botaniker,' 

 (Berlin, Keimer : 8vo, pp. vi. 308.) — A. V. Coenil & V. Babes. 

 ' Les Bacteries et leur role dans I'anatomie et I'histologie patho- 

 logique des maladies infecteuses.' (Paris, Alcan : 2 vols. Bvo. pp. 

 viii. 696, tt. 27). — H. Fol, 'Les Microbes.' Geneva, Georg : 4to, 

 pp. 54, tt. 5). — F. RocHAS, 'Les Schizophytes.' (Geneva, Georg: 

 pp. 27). — J. C. Brown, ' Forests and Forestry in Poland, Lithuania, 

 the Ukraine, and the Baltic Provinces.' (Edinburgh, Oliver & 

 Boyd : pp. viii. 276). — S. Artault, ' Glossologie Botanique.' Paris, 

 0. -Henry : 12mo, pp. 328). — G. Hauser, ' Ueber Faulnissbacterien 

 und deren Bezielmngen zur septicamie.' (Leipzig, Vogel : 8vo. 

 pp. 94, tt. 15). — A. Paillieux & D. Bois, 'Le Potager d'un Curieux.' 



