Geology and Natural History. 325 
very largely to work done either by him or in the Wirzburg 
laboratory. The notes do not pretend to cover the literature of 
the subject. 
, 40 many American students of Botany, Professor Van Tieghem 
is known as a successful investigator of some difficult problems 
In histology and physiology, and for his work in the department 
of cryptogamic botany. But he is more widely known in this 
country as the editor of a French translation of Sachs’s Text-book. 
portional share of attention. This book closes with a study of 
close fertilization, cross-fertilization and hybridization, and wit 
rae f the origin of species. Of the latter, the 
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"nsolved without it.” “ But if we wish to preserve to this theory 
The second part of the work is devoted to a special 
the orders of lower and of higher plants. The arrang 
