EVOLUTIOy BY MEAXS CF HYBRTDTZATrOX 61 



Further, as the spot where the mating of such gametes takes place is 

 as indifferent to the effect as is the origin of the gametes, the same 

 species may be born at different spots, that is to saj^, species may 

 arise polytopically. 



This theory is disastrous to phylogeny. Since the source of the 

 uniting gametes is a matter of indifference, similar individuals may 

 arise from widely different sources, and similarity is therefore no 

 guide to relationship. Hence phylogeny, or reconstmction of what has 

 hap]:)ened in the past, is merely a product of fantastic speculations. 



Dr. Lotsy extends his theory to include the origin of the great 

 grou])s of plants. A new class is merely the result of a happy 

 meeting between two sufficiently differently constituted gametes. 



In order to study the constitution of the gamete the author 

 suggests the advantage of dealing with haploid organisms, the result 

 of a single gamete, such as a moss-plant, rather than diploid organisms, 

 like the higher plants, which are the result of the interaction of two 

 gametes. Moreover, if it could be proved that a moss-plant were 

 able to produce more than one kind of gamete, niutation would have 

 been proved in so far at least as we should be justified in concluding 

 from such a result that a monogametic organism can become 

 polygametic without the direct interference of a cross. 



A. B. R. 



A Tfwfbook of Botany for CoUerfes. By William F. Gaxoxg, 

 Ph.D., Professor of Botany in Smith College. Xew York : The 

 Macmillan Company. 8vo, pp. xii, 401. Price 86*. Qcl. net. 



Professoe GAXOxa earned the gratitude of teachers by his 

 previous work, The Teachinq Botanist. His present book appeals to 

 a different class of readers, for whom there is, perhaps, more provision 

 in existing manuals. It is meant not for those beginning a botanical 

 career but for the general student ; and for this purpose it seems to 

 us admirably adapted- It deals with general anatomy — -or, as it is 

 commonly miscalled nowadays, moi'^jhology — and physiology, syste- 

 matic botan}^ being reserved for a second volume, and is mainly 

 contined to Howering-plants. As might be expected from its authorship, 

 the physiological aspect is fully emphasized and elucidated, while such 

 comparatively new topics as chemosynthesis, enzymes, the rise of 

 water by traction, chimajras, Mendelism, mutations, and double 

 fertilization ai-e succinctlv but clearly dealt with. If American 

 authors wish for the circulation of their books in this country, they 

 should add the scientific names of the examples cited : such names as 

 •'Bunch-grass" or '"Spanish bayonet" will conve}" little meaning to 

 English readers. 



The book is fully illustrated with figures of physiological apparatus 

 and with many old acquaintances from various sources, for the use of 

 which the authoi- makes a spirited apology on the same grounds as did 

 Sir Roger de Coverley for his chaplain's borrowed sermons, that they 

 were better than his own would be. The original diagrams here 

 certainly bear out this view. It is hard that the popular French 

 author, Louis Figuier, whose work is drawn u]X)n, should be consistently 

 misrepresented throughout as •' Figurier." 



G. S. B. 



