246 On the Perspiration 
But, what is most wonderful, they both arrive at the proper result, 
though by different means: since they both tried the experiment 
of placing a plant without water, without earth, but in a very moist 
atmosphere, and the plant has remained alive, nay, increased in 
weight, while another vegetable placed by its side in the same cir - 
cumstances has died directly,—proving that the first. absorbed 
all its nutriment from the atmosphere, and had no radicles to its 
roots; and that the other was an earthy plant receiving its nourish- 
ment from the ground and through radicles alone. 
But the hairs are not designed for absorption only, or one sort 
of form would have sufficed: whereas in each vegetable there 
are often many differeut-shaped figures, continually accompanied 
with valves, and various species of mechanism of the most curious 
kind. There are two sorts of these hair-like figures or instru- 
ments in the Sweet Pea; two in the Zinothera; three in the 
white Antirrhinum; three in the Lamium allum, and one ad- 
mirable for its mechanism made nearly the same as in the Nettle, 
but without its poisonous juices. Nature never multiplies her 
means when one end only is in view and is to be answered. Will 
not then common sense explain the design Nature proposes in 
thus multiplying the figure of the hairs; or rather in forming 
different instruments in the same plant, and conclude these sorts 
of hairs were intended to effect a change in the juices entered 
within them, and produce that alteration the species of plant 
may require, and to confirm and establish that result? The 
hairs may be seen to change the colour of their juices after en- 
tering a vapour or sort of cloud which gets secreted between 
the valves; the hair afterwards admits another juice, and these 
coming into contact, mix and explode, and produce the altera- 
tion required. This is always the case with those instruments 
which compound the oil for the vegetable, and which are quite 
of a different shape from all other hairs, as in the Sun-flower 
plant, &c. Why all this mechanism and variety of forms, if it 
was only to admit a single juice, and that no alteration was to 
be effceted by the liquid by means of the instrument? A simple 
pipe would have done as wel/. Numbers of my friends have 
seen this phenomenon; men of the greatest ability will 
testify to its truth, if seen in the compound microscope, and 
they have seen the hairs afterwards twist or flatten, and all the 
Juices forced down into the leaf. In the Rose, the liquid enters 
the hair, the tint of water; and if it is watched for an hour or 
two, a thin vapour will be seen to insinuate itself and mix with 
the other juice : in a short time they explode ; and so violent is 
the effect produced that much of the liquid is thrown out of the 
ball, and may be seen scattered all around; at last all subsides, 
and the liquid becomes a deep red. J remember showing whet 
this 
