186 SCIENCE PROGRESS 



plants, are insects belonging to various families of hemiptera, diptera, hymenop- 

 tera, and a relatively small number of coleoptera and lepidoptera ; while the 

 plants attacked range from Alga? and fungi to the Compositae — indeed there are 

 probably very few species of flowering plants on which galls may not be found 

 either frequently or occasionally. Hence it is not surprising that the study of 

 animal-induced galls (zoocecidology) is pursued by a large and enthusiastic body 

 of workers, mainly field-naturalists who confine their attention to external form 

 and the determination of the species of insect and plant concerned in gall pro- 

 duction. The investigation of the histology and physiology of galls has, as might 

 be perhaps expected in a branch of biology which appeals both to botanists and 

 zoologists, and is therefore apt to be neglected by laboratory workers in both 

 departments, lagged behind the purely systematic study of zoocecidology, though 

 it offers a most attractive field for research and the results already obtained are of 

 the greatest interest from many points of view, both biological and biochemical. 

 The work of Peyritsch, Beijerinck, Kiister, and others has shown that the detailed 

 study of galls and gall-formation may throw light upon many problems in the 

 physiology and pathology of plants, and the considerable and increasing 

 literature of the subject indicates that this study has before it a future of great 

 promise. 



Meanwhile, biologists owe a debt of gratitude to the labours of M. Houard in 

 compiling his great work, of which the volume now issued is the third part, con- 

 sisting of pp. 1249 to 1560, with figures 1366 to 1566. As the author points out, 

 since the appearance of the first two volumes the study of galls has shown extra- 

 ordinary development, and this supplementary volume, based on four years of 

 cecidological work, contains descriptions of 1,300 galls, giving the names of over 

 500 species of gall-producing animals and of 300 new plant " hosts," with an 

 extensive bibliography, and finally zoological and botanical lists which facilitate 

 reference to the body of the work. This volume, like its predecessors, is indis- 

 pensable to all who are interested in galls ; it is admirably arranged, and the price 

 is very moderate. 



F. Cavers. 



Cabinet Timbers of Australia. By R. T. Baker, F.L.S. [Pp. 186. With 68 

 coloured plates.] (Sydney: Technological Museum, 1913.) 



This handsome volume forms No. 18 of the valuable Technical Education Series 

 published by the New South Wales Government, and contains an Introduction 

 written by the State Minister of Public Instruction, who aptly remarks that the 

 colour, figure, and other characters here portrayed of the various species, by 

 colour photography, may come as a revelation to those not intimately acquainted 

 with the timbers themselves. The letterpress is practically limited to brief but 

 adequate descriptions of the various timbers, which are illustrated by sixty-eight 

 exquisite coloured plates. These fine plates alone render the book of great 

 value ; and it is greatly to be desired that plates of this kind, showing the natural 

 colour and graining of timbers, may be published in other timber-producing 

 countries. The importance of works like this is far-reaching ; for apart from 

 their more immediate value in the technology of timber and in cabinet-making, 

 the bringing together of useful and beautiful timbers in this particular form should 

 do much to stimulate the movement for the setting aside of forest reserves and 

 for extensive afforestation in regions where valuable forests are in danger of 

 extinction. 



F. Cavers. 



