— 100 — 



calyXj when exerted for the purpose of opening or 

 closing the corollas or calyxes of the florescence. They 

 act also as resistants to external irritation or internal 

 sensations of discomfort in the plant individual, 

 making efforts to prevent or remove sensations which 

 annoy, or to encourage those which are necessary and 

 agreeable. They act under the stimulus of light, 

 turning the upper side of the leaf to the point most 

 favorable for receving that stimulus. 



The Abbe Teasier ( Hist, de I'Academie Eoyal 

 ann. 1 783 ) exposed a variety of plants, in a cavern to 

 different quantities of light, and demonstrated satis- 

 factorily that the contraction or elongation of muscular 

 action in plants, or, in other words, their elasticity, 

 was sensibly affected by the presence or absence of 

 light. 



Here in Mauritius, instances of muscular dilatation 

 and contraction abound, and to the observant eye are 

 very evident. 



Plants are known to change the direction of their 

 roots or trunks, as, for instance, where a plant has 

 been inverted intentionally, or placed root uppermost , 

 the root makes an effort to curve downward, and the 

 stem upward, until it regains its natural and proper 

 direction. Acted upon by the air, sun, and light the 

 muscles direct the upward course of the stems ; and 

 acted upon by the moist warm vapors in the ground, 

 they also determine the direction of the roots. While 

 in some species the muscles are robust and powerful, 



