i)8<; JOURNAL OF KORKSTRV 



plant by developing a rhizome (making the stem grow underground as 

 Constantin has done) ; transplanting into the snow region of the Alps 

 and into sand-dunes produced the same result. On the other hand, 

 Bonnier by subjecting certain plants to continuous electric light changed 

 their structure and their functions, so that they assimilated and grew 

 at the same time. In a few months change in structure took place that 

 hitherto would have been believed as requiring centuries : pine, spruce, 

 beech, etc., changed structure of leaves so as to lose the characteristics 

 of their genus ; the formation of "shade leaves" and "light leaves" dif- 

 ferent in structure and function is well known. The effects of change 

 in light conditions is practically used by foresters in thinnings. By 

 varying light intensities Maige succeeded in changing straight stems 

 into creeping ones and vice versa (reptation !). 



An interesting case of change of habit in northern climate is reported 

 from the peninsula of Kola (Russia), where the railroad engineers 

 found what appeared like young birch reproduction, the branches of 

 birch boles growing underground. 



In conclusion, the operation, in combination, of environmental influ- 

 ence and the theory of mutation seems to satisfy most cases ; the former 

 readily observed, the latter somewhat more obscure, because the latent 

 characters have in nature rarely opportunity to assert themselves. 



The reviewer concludes in argiting for a more circumspect selection 

 of seed and plant material. 



Revue des Eaux Forets, June, 1918, pp. 127-133. 



SILVICULTURE. PROTECTION. AND EXTENSION 



Foreseeing that the damaged woods in the war 

 Insectivorous zone, especially the coniferous ones, are bound to 

 Bats be iM'oHfic breeding places for insect pests, Jolyet 



proposes systematic breeding of bats as most 

 assiduous insect destroyers, and as they take the insects in their butter- 

 fly, stage they do not destroy at the same time the parasites, which are 

 present in the caterpillar stage. He ex])ects to attract the bats by pro- 

 viding suitable resting places for them in the daytime in the form of 

 1x)xes. the precise construction of which is described. The bats are 

 collected — brought to their habitation, preferably during their winter 

 sleep, in December, when, provided with a warm bed made with hay or 

 straw, they are locked in for several months and become accustomed 

 to their habitation. 



