98 Comparative Anatomy ; or an Attempt at 



from the ends of the nerves on the cutis. The use of this last 

 skin is to protect the delicate nervous fibres which stand out 

 from the true skin : it increases by pressure ; and the more 

 scales are added;, the less that nervoiis se7isibility isj'elf. This 

 is the reason that hard-working people can put their hands in 

 the fire or in extreme hot water, wirliout being sensible of [)ain : 

 the more this skin is increased, the less feeling they possess. 



As the plant has no nerves, it can have no feeling; and as it 

 has no perspiration, it can have no pores. The mark'. n in 

 the skin are merely the effect of the opening of the balls m the 

 second and third cuticle, which contain first the water and then 

 the oxygen. The first cuticle is perfectly impervious to water, 

 and completely like gold-beater's skin, without figure. Air, 

 however, passes it freely : but for this skin, how could the water 

 be retained to be decomposed? 



I have said that there is no perspiration in plants ; indeed it 

 was perfectly impossible that the vegetables could decompose 

 water to give out oxygen, and at the same time perspire such 

 quantities — and yet have juices enough left to support the plant. 

 It seems to me that tlie incomparable Mirbel almost owned his 

 unbelief long ago: — that those bubbles taken for water have 

 proved to be irtstruments of various kinds and forms, and show 

 themselves to be undoultedly the most beautiful and compli- 

 cated part of the vegetable arrangement. As in the animal body 

 there are such a variety of secretions from the blood, which re- 

 quire an immense mechanism, not suited to the general simplicity 

 of the form of a plant, so in its stead Nature has contrived that 

 it should receive from the atmosphere, by means of these instru- 

 ments or hairs, all the juices necessary to the vegetable, in lieu 

 of forming them by secretion: but they are not received in their 

 perfect state, but often alter greatly between their entering the 

 valve and flowing into the plant : nav, I have frequently known 

 two liquids enter the liairs and secrete themselves between the 

 two different valves; then meeting explode, and compose a third 

 juice, and thus form by chemical affinity the matter which the 

 plant requires. This is really the most beautiful part of the 

 study of plants ; and to chemists would (I should conceive) serve 

 as an elucidation to ma?nj points, if they would condescend to 

 try them. Even oil is received by the hairs in a sort of vapour, 

 and only becomes oil when it reaches the first liquid ; and they 

 both enter the third valve purified and completed. I have 

 watched the various liquids inimmerable times ; nay, I might 

 truly say, for months together — their manner of filling and empty- 

 ing their hairs — the variety of their juices — the curious changes 

 made in them — and the getting rid of the obnoxious part by 

 means of the outward cuticle of the hair, and then sending down 



into 



