340 . SUPPOSED ANALOGY OF CYCLOSIS, [BOOK n. 



oscillation of the globules. They have an incessant tendency 

 to unite and to separate, without the one tendency ever 

 overcoming the other; and, as the organic (molecules) 

 elements of vessels are of the same nature as the globules 

 of latex, it follows that the walls of the vessels, and the 

 globules they contain, have the same tendency to approach 

 and retreat, as the globules themselves have with respect to 

 each other. As this motion of coming and going takes place 

 in a determinate direction, it necessitates and regulates the 

 progressive motion of the latex. 



7. Cyclosis is analogous to the motion of the blood in the 

 lower animals, such as Nephelis vulgaris, Planarias, Nais 

 proboscidea, and Diplozoon paradoxum ; or in the foetus of a 

 fowl, before the heart is formed, when, as Malpighi and 

 Wolff have shown, the blood moves spontaneously in the 

 vascular apparatus. Nevertheless, although there is in plants 

 no heart, or centre of circulation, according to M. Schultz, 

 there are certain foci, concerning which he speaks thus 

 (Comptes rendus, vi. 583.) : In Commelina coslestis there is 

 a bundle of laticiferous vessels, which are very delicate and 

 filamentous, compact and united in the form of a net with 

 very long meshes, in which are perceptible currents of latex 

 ascending, descending, and returning upon itself. Besides, 

 at the side of the focus, in the cellular tissue, we remark the 

 cyclosis in distant currents, and the same thing is visible 

 between the cells of the hair. It is observed that the scat- 

 tered currents, whether in the cellular tissue of the stem, or 

 in the hairs, are neither separate in each cell nor isolated 

 throughout the cellular tissue, but united to the focus of 

 circulation in certain places ; so that all the latex circulating 

 in the cellular tissue and the hairs is derived from the focus 

 of the cyclosis. The same things are still more distinctly 

 visible in Campanula rapunculoides. 



Cyclosis may be easily seen in the stipules and bark of 

 the Fig, especially of Ficus elastica; in the leaves, and 

 even the valves of the fruit, of Chelidonium ; and in the 

 bark of Acer platanoides. In no case, however, is it seen 

 more easily than in the interior sepals of Calystegia sepium, 

 which are thin enough to bear examination, without laceration, 



