maivj hnportant Truths hi 'Phylology. 101 



of water will be seen to ooze from the plant, though (if any 

 escaped) the magnifier would make the bubbles as big as over- 

 groi'j/i pens. But it escapes in air ; and the joint gases again 

 compose the water, and which runs down the glass. 



The philosophers of the last century, not being in the liabit of 

 examining plants with the microscope, thought all those figures 

 <liscovered on the cuticle of the leaves were uncovered bubbles 

 r.f water, because they appeared clear and yjellucid. But all 

 these figures are either cuticles formed by balls standing on high 

 pedestals, or figures of a still more curious make, resembling retorts, 

 cucurbits, and cylinders of various sorts and sizes, divided by re- 

 gular valves, and formed to produce vacuums, to separate water 

 into its component parts ; in short, established for every purpose 

 of chemical affinity ; by which means the juices are received from 

 the atmosphere, and changed to the manv compounds necessary 

 to compose the various juices of the plant. That balls standing 

 on stalks or long retorts cannot be perspiration, every one will 

 readily oivn : — but to make the matter plainer still, take two 

 plants of the same sort, expose one to the open atmosphere ; 

 shade the other above. The first will be probably covered with 

 dew; the other will remain perfectly dry, not the smallest drop 

 appearing on the leaves. Where then is the perspiration ? Place 

 this plant in a room, and it will receive dust like any other fur- 

 nitiu-e ; nor will that dust agglutinate or thicken : on the con- 

 trary, the smallest breath of wind will disperse and blow it all 

 off, leaving the leaves perfectly clear : — a positive proof that no 

 water can ooze from the leaves, or they would exactly resemble 

 the plant when disordered with the honey-dew, and be as nasty 

 in appearance as they then are. And how deformed Nature 

 would be ! for one of its greatest beauties is the vivid green and 

 cleanliness of its shrubs and trees. Would not the dust stick on 

 every part, and spoil all its beauty; or roll off in large balls, 

 smearing the leaf as it passed? It is astonishing that this ob- 

 jection should not occur as so very obvious. 



The next proof I shall give of the impossibility of perspiration 

 is, that every vegetable possesses an impervious skin, through 

 which not a drop of water can pass. To understand and be cer- 

 t-ain whether plants do or do not possess a skin capable of shut- 

 ting out all outward moisture, independent of the figures or hairs 

 already mentioned, 1 procured with great labour near thirty 

 fliffcrent specimens of this impervious cuticle, in which however 

 1 must observe that the pores were most conspicuous. The skins 

 were; taken from the outward cuticles of leaves, stems, and petals 

 of various plants. Placing them on a glass, with the interior 

 ■ide upwards, I rubbed with the greatest care, with my finger 

 "'V.'Tcd with very fine cambric, and soon found that my con- 



(i 3 jectures 



