102 On the Anatomy of Vegetahles; intended to siilsiantiate 



jectures were right; that the mark was only that of the open- 

 ing pabulum below, impressed by constant motion on the upper 

 cuticle; since after yr?c/io« it left behind neither ()Oie nor pat- 

 tern, but an impervious skin so very fine that not even the solar 

 microscope could display its net-work. Their skins were almost 

 all alike, though some were thicker than others : — some indeed 

 are so very transparent that the liquid appears uncovered, till you 

 touch it, and prove that it is contained in a vessel, which, though 

 so thin, is also so strong as repeatedly to bear detonation.. Just 

 the same is the cuticle with which most of the sand plants are 

 covered, which take in so much nutriment. Just tlie same is 

 the skin which covers most plants, but which is so very transpa- 

 rent, that I am often obliged to place a hair with it in my sliders to 

 mark that there is an object there, — as it is to be seen by the naked 

 eye only when placed in a cross light. With such a skin, then, 

 how can the water pass in and out of the vegetable, but by 

 means of the hairs? And if there was no such cuticle, how would 

 the decomposition of water be effected? since the liquid would 

 leave it at one pore, as fast as it entered at the others : — wliereas, 

 secured by this skin, it is to be seen under the cuticle bubbling 

 into air, just as it does when exposed to the Galvanic wire in a 

 glass tube, when water is decomposed. It is by the consistency 

 of my plan that the truth of the whole should be tried. One pro- 

 position proves the next — till, copied from Nature, it forms one 

 circle of facts, my mind was wholly incapable of suggesting, ex- 

 cept by being led through them by living specimens. Sure no 

 more reasons can be wanting to prove the mistake which philo- 

 sophers have made in this respect. But there are two or three 

 more as convincing. 



The sand plants, the rock plants, take almost all their nutri- 

 ment from the atmosphere, their roots being incapable of be- 

 stowing any, or at most a very trifling quantity. But if they 

 are to lose again in perspiration the greatest part of what they 

 receive, how are they to be nourished? It is the want of the 

 impervious skin in the rock plants, which leaves them open to 

 imbibe all the nutriment they require, being almost withcxit 

 hairs, but receiving the dew, &c. direct as it /alls. But the 

 sand plants, having a qnantily of hairs and instruments, have 

 the impervious cuticle, absorbing through these hairs an exces- 

 sive quantity of nourishment, vvhich thus enters the plant. It 

 was these plants that were said to perspire so much, and it was 

 this liquid collected from the broken instruments that they called 

 perspiration; whereas it is all to be seen entering the plant from 

 every hair, and thus meandering in vessels made for the pur- 

 pose. 



Of what use could perspiration be to plants that have little or 



