On the No7iriskmenf produced to the Plant ly its Leaves. 5 



ways a sliiiiing cuticle above the impervious one, into which 

 points or pockets are so contrived as to recmve the moisture 

 from the atmosphere : see fig. <], 4. It is a shining net very fre- 

 quently taken for perspiration, indeed it is continually filling with 

 water, but instead of ii;iiung it out it is taking it in. The 

 quantity of water or difterent liquids received by means of the 

 cuticles of this species of sand plant is excessive; but they not 

 only draw nourishment from the hairs and the cuticle, but the 

 side of each leaf is a reservoir for accumulating nutriment round 

 the plant: see fig. 5, 6. In the turnip they are a sort of retort, 

 filling and emptying into the vegetable every three or four hours; 

 ' fig. 6, full ; eiripty 1 . I often find them all empty, on generally 

 one side of the leaf at a time ; and these when thus situated 

 plainly show how the hahs axe formed: see fig. 8, 9. The 

 glazed matter with win'ch they arc made, appears to me ex- 

 actly to resemble the impervious skin (so often mentioned) at 

 the exterior oi each face of the IcaJ'. The texture is the same, 

 and it is also exactly like the shining skin which forms the cuti- 

 cle of tiie sand plant I have just described; wliich, whether full 

 or empty, makes so shining and brilliant an appearance in the 

 microscope, that without taking it oflf it cannot be ascertained 

 whether it is full or not of moisture ; ])ut the hairs, as soon as 

 they empty themselves into the plant, grow as flat as their valves 

 will let them. When vacant, they often draw up like a cork- 

 screw, if they have many valves ; but if only two, one at each 

 end, they hang like a wet rag till refilled. I have found this 

 species of gauze both striped and fipotted, and in some plants it 

 is sn thick as wholly to disguise the colour of the liquid it con- 

 tains. But wherever seen, and in whatever plant found, it is the 

 satr.e 7natter, with trifling variations, always impervious to water, 

 and, though so very flight, capable of bearing even detonation — 

 which I have often seen two liquids, on meeting, produce in ths 

 retort while under my eye. These innumerable hairs are the 

 principal marks of a sand plant. 



To give a perfect idea of the means used in nourishing a pa- 

 rasite plant, I need only describe the method by which innume- 

 rable loads of small muscles fasten themselves so forcibly on tlie 

 rocks upon our coast. The muscle has a broad round part, 

 hollow in the middle ; the shell is laid on the rock with a ge- 

 latinous matter which fills up all the interstices of its scollop 

 except the middle cavity, which is full of air: this the fish either 

 exhausts or draws inward for its own use and support, t;hus 

 leaving a vacuum, which fastens down the shell more powerfully 

 than any glutinous licjuid cuuld do. In the same manner is the 

 fjump of the parasite plant composed ; it has a broad piece which 

 is held down by means of a vacuum^ managed on the nurse plant: 

 A 3 but 



