POLYGAMIA. 



tirely exposed to the open air have very little motion, 

 bat remain in one state, neither expanded nor closed, 

 but between both, especially in cool weather 5 nor do 

 these shut themselves at night, as those which are in 

 a warm temperature of air. 



" Secondly, it is not the light which causes them 

 to expand, as some have affirmed who have had no 

 experience of these things ; for in the longest days of 

 summer, they are generally contracted by five or six 

 o'clock in the evening, when the sun remains above the 

 horizon two or three hours longer ; and, although the 

 glasses of the stove in which they are placed are co- 

 vered close with shutters to exclude the light in the 

 middle of the day, yet if the air of the stoves be warm 

 the leaves of the plant will continue fully expanded, 

 as I have several times observed. Nor do these plants 

 continue shut till the sun rises in the morning, for I 

 have frequently found their leaves fully expanded by 

 the break of the day ; so that it is plain the light is 

 not the cause of the expansion, nor the want of it the 

 cause of their contraction. 



" I have also observed, that those plants which 

 are placed in the greatest warmth in winter, continue 

 vigorous, and retain their property of contracting on be- 

 ing touched j but those which are in moderate warmth , 

 have little or no motion. 



" When any of the upper leaves of these plants 

 are touched, if they fall down and touch those which 

 are below them, it will occasion their contracting and 

 failing, so that by one touching another they will con- 



