676 CONSERVATIVE ORGANS. f^LECT. XI. 



writer*, however, the rising is ascribed to the 

 contraction of the " fibre," or costa connected 

 with the hinge, u by the hot and dry atmo- 

 sphere," and the shutting, to its expansion when 

 the air is saturated with moisture ; while by others 

 again, these movements are regarded as spon- 

 taneous or dynamical, like some other of the 

 movements of plants. In reviewing these opi- 

 nions the first might be considered probable, as 

 far as concerns the immediate or mechanical 

 cause of the change in the position of the lid, 

 but it does not satisfy the mind; and we na- 

 turally inquire, what occasions the afflux and 

 receding of the fluids to this particular set of 

 vessels ? for, without an answer to this query, 

 we have gained little by the information afforded 

 us, admitting it to be correct, respecting the state 

 of the vessels. The second opinion is less pro- 

 bable, because we cannot conceive how the costa 

 in question can contract, without producing a cor- 

 responding contraction of the whole back part of 

 the pitcher, the consequence of which would, ne- 

 cessarily, be to raise the lip of that vessel to the 

 same elevation as the lid, and thence to place it 

 in the same relative position to that part as it pre- 

 viously maintained. Lastly, the idea of explain- 

 ing the phenomenon, by saying, that it is a spon- 



* Mr. Barrow. 



