NOTICES OF BOOKS AND MEMOIRS. 879 
lower looser parenchyma having much air entangled between the 
do with the diminished liability of the lower side to 
suffer from chilling ? 
complex of these phenomena. Certain plants which are especially 
cultivated on hot hill-sides sometimes suffer severely from chilling 
the statement that the cotyledons of Mimosa pudica are placed 
vertically upwards, and face to face at night, though the first leaf 
drops its rachis like a serhaphore, and folds its leaflets forwards in 
an imbricate manner, as do older ones. 
Besides sleeping movements, the authors enter into the 
‘on and discussion of two other forms of modified circum- 
nutation; those caused by the direction of incident light,— 
nyctitropic movements being determined by changes in the 
intensity of surrounding 
gravitation. Chapters vill. and 1X. e occupied with the 
important subject of heliotropic movements. If it is of advantage 
rebel, and circumnutatio 
forward movement towards the source of light. 
es of obedien . the new impulse seem to be 
any 
part very complex problems to be d cal 
The student will gain a deep insight, 
8 the 
be considered solved. 
