278 PHILOSOPHICAL NOTES ON 



" I£ we do not govern words, words will govern us," said an 

 eminent student of words. 



The basis of distinction on account of anatomical structure, we 

 see, breaks down at the threshold of the inquiry. What remains 

 for us to investigate now may be indicated by the question — is 

 there any morphological distinction between a trichome and other 

 parts of a plant ? 



Prima facie^ common sense would refuse to make an essential 

 distinction between a trichome and a branch when it is considered 

 that the former can now be a trichome and then a branch.* In 

 the same way that it refuses to make an essential distinction 

 between leaf, stamen, carpel, stipel, and gland when the first can 

 be transformed into any of the others, or vice versa. 



It appears that botanists have made a distinction between 

 hairs and other structures on the ground that they are outgrowths 

 of the epidermis, as if the epidermis had fallen from the clouds, 

 and had no connexion whatever with the development of the 

 plant. The trichome has hitherto been looked upon as a sort of 

 entity independent of all other cells, and not as an atrophied 

 member of a colony. 



Originally there was no such thing as epidermis, because it 

 had no raison d'etre. A differentiated cellular layer on the 

 external surface of plants appeared only when they emerged from 

 a water life. The epidermis, both in animals and plants, is 

 evidently conditioned by the dryness of the atmosphere under 

 certain circumstances. It thus protects the subjacent layers of 

 cells from that very dryness which originated the epidermic layers, 

 so that the functions of all the cells enclosed within the epidermic 

 bag might be carried on without direct interference from atmos- 

 pheric changes, or, at all events, with as little interference as 

 possible. 



Even in those phaenogams which have some of their leaves 

 submerged, as in Ranunculus and others, the differentiated layer 

 known to histologists as epidermis is wanting in the submerged 

 leaves. 



I am aware that through the stomata the external air can find 

 its way into the interior of the leaf tissue, but besides the passage 



* The simple trichomes of Begonia phyllomaniaca of the stem, petiole, 

 and blade turn into branches furnished with leaves ! 



