242 FREAKS OF PLANT LIFE. 



whilst the leaves do not. In others the cotyledons 

 do not move, whilst the leaves are remarkable for their 

 sleep movements. In some plants the cotyledons rise 

 vertically upwards, whilst the leaves move downwards, 

 and in others the reverse takes place. Reflecting on 

 the reason why this movement should take place in 

 the cotyledons, this author is of opinion that the 

 movement, by means of which the blade is made to 

 rise or fall almost vertically at night, has been acquired 

 for some special purpose, and he does not doubt that 

 purpose to be the protection of the upper surface of 

 the blade, and perhaps also of the little central bud,, 

 or plumule, from radiation at night. 



No sane person, reading over the details of ex- 

 periments like these, would hesitate in the conclusion 

 that, whatever the reason may be, there must be some 

 adequate and sufficient cause for the movements 

 which the cotyledons and other plant organs exhibit. 

 That such movements are merely matters of chance 

 is a position wholly untenable, but their orderly and 

 systematic recurrence leads at once to the conclusion 

 that, however much we may differ in our speculations 

 as to the probable reason why such movements take 

 place, there will be no doubt in our minds that they 

 are the agents in some work which is beneficial to the 

 plant which exhibits them. The theory suggested 

 seems to be a sufficient one, and not opposed to 

 known facts, and it appears to be one which is justi- 



