NOTE XR XXNTEZ VEGEDABEECIRCUL ATION 445

blood; though this efuſion was ſlower from the root-end than from the ſummit-end, from whence I concluded, that the arteries of the root-end had ceaſed to act, and that the returning veins continued to bleed; and on the contrary, that the veins of the ſummit part had ceaſed to aet, and that the deſcending arteries continued to bleed. And laſtly, that the circle of red points in both of them were the mouths of the abſorbent ſyſtem, which continued to a& in both directions. And 1 was thus induced to be- lieve the exiſtence of a venous ſyſtem correſponding to the arterial one in the barks or roots of plants, as well as in their leaves and petals.

There is however another part of the circulation of vegetable juices viſible to the naked eye, and that is in the corol or petals of flowers, in which a part of the blood of

the plant is expoſed to the influence of the air and light in the ſame manner as in the foliage, as will be men- tioned more at large in notes XXXVII. and XXXIX.

Theſe circulations of their reſpective fluids ſeem to be carried on in the veſlels of plants preciſely as in animal bo- dies by their irritability to the Rimulus of their adapted fluids, and not by any mechanical or chemical attraction, for their abſorbent veſlels propel the juice upwards, which they drink up from the earth, with great violence; I ſup- poſe with much greater than 1s exerted by the lacteals of animals, probably owing to the greater minuteneſs of theſe veſſels in vegetables and the greater rigidity of their Coats» Dr. Hales in the ſpring KE cut off a vine near the ground, and by fixing tubes on the remaining Kump obi; found the ſap to riſe twenty-one ei in the tube by

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