REPRODUCTION OF PLANTS. 93 



process of germination is obstructed by the in- 

 fluence of light on the surface of the soil, although 

 the bulbs and seeds have been buried some depth 

 beneath it."* 



" One very remarkable result," says Mr. 

 Hunt, " must be noticed ; under all ordinary cir- 

 cumstances plants bend in a very decided manner 

 towards the light. In all my experiments with 

 red fluid media, they hare as decidedly bent from 



* " Researches on Light," p. 191. 

 t Ib. p. 319. 



A very curious phenomenon which from its usually 

 taking place in the evening has been called the sleep of 

 plants, appears to be principally owing to the influence 

 of light. The fact itself is, that in certain plants the 

 leaves fold up, and sometimes grasp the stem. It occurs 

 also in some flowers which shut up periodically, and the 

 inference that light is probably the agent in producing 

 this effect, was drawn by M. de Candolle from the cir- 

 cumstance that he found the period of its occurrence 

 could be reversed by excluding the light from the plants 

 during the day time, and placing them in strong lamp 

 light at night. (De Candolle, Pliys. Veg. vol. ii. p. 

 860.) 



It was remarked in an earlier part of this little work, 

 that the influence which the study of one science has on 

 many others, with which it appeared in the first instance 

 to promise no connection, was illustrated by the benefit 

 that agriculture derives from chemistry ; another proof of 



