INSECTIVOROUS AND CLIMBING PLANTS. 32T 



as when attracted into the flame of a candle. In the 

 tobacco-plant, for instance, Mr. Darwin could find no 

 evidence that the glandular hairs absorb animal mat- 

 ter. But Darwinian philosophy expects all gradations 

 between casualty and complete adaptation. It is 

 most probable that any thin-walled vegetable structure 

 which secretes may also be capable of absorbing under 

 favorable conditions. The myriads of exquisitely- 

 constructed glands of the Chinese primrose are not 

 likely to be functionless. Mr. Darwin ascertained by 

 direct experiment that they promptly absorb carbon- 

 ate of ammonia, both in watery solution and in vapor. 

 So, since rain-water usually contains a small percent- 

 age of ammonia, a use for these glands becomes aj^par- 

 ent — one completely congruous with that of absorbing 

 any animal matter, or products of its decomposition, 

 which may come in their way through the occasional 

 entanglement of insects in their viscid secretion. In 

 several saxifrages — not very distant relatives of Dro- 

 sera — ^the viscid glands equally manifested the power 

 of absorption. 



To trace a gradation between a simply absorbing 

 hair wdth a glutinous tip, through which the plant may 

 perchance derive slight contingent advantage, and the 

 tentacles of a sundew, with their exquisite and asso- 

 ciated adaptations, does not much lessen the wonder 

 nor explain the phenomena. After all, as Mr. Dar- 

 win modestly concludes, " we see how little has been 

 made out in comparison with what remains unex- 

 plained and unknown." But all this must be allowed 

 to be an important contribution to the doctrine of 

 the gradual acquirement of uses and functions, and 



