146 



CYOLOSIS. 



capillary circulation of animals. On account of these movements in the 

 latex, the laticiferous vessels have been denominated Ginenchymatous 

 (xiviui, 1 move), and the movements themselves are included under 

 the name Gyclosis (^auxXog, a circle). 



The plants in which the movements are best observed are those 

 having the latex mUky or coloured, such as various species of Ficus, 

 Euphorbia, and Ohelidonium. In fig. 241 there is represented 



a small fragment of a leaf of 

 Ohelidonium majus (celandine), 

 which shows the current of 

 orange granules in the lati- 

 ciferous vessels, their direction 

 being indicated by arrows. If 

 the young unexpanded sepal of 

 the Celandine is removed from 

 the plant, and put under the 

 microscope, or if the inner 

 lining of the young stipule of 

 Ficus elastica be treated in a 

 similar manner, very obvious 

 motion is seen in the granular 

 contents of the vessels, and 

 this motion is modified by 

 pricking the vessels or by pres- 

 sure. If the microscope be 

 applied to the stipule of Ficus 

 elastica, while still attached to 

 the plant and uninjured, pres- 

 sure with any blunt object on the stipule will be observed to cause 

 a marked oscillation in the vessels, thus showing their continuity. 

 There will also be seen a regular movement from the apex towards the 

 base, independent of external influences, when the stipule is allowed 

 to lie on the field of the microscope without any pressure or injury 

 whatever. This movement has been observed to continue for at 

 least twenty minutes. It is of importance to distinguish between 

 those molecular movements which are caused by injury and pressure, 

 and those which defend on changes going on in the interior of the 

 living plant; The elaborated sap descends through the vessels of 

 the liber. 



It appears, then, that in the case of Exogenous plants, the fluid 

 matter in the soil, containing different substances in solution, is 

 absorbed by the extremities of the roots, ascends to the stein, passes 



Pig. 241. Bmall portion of the leaf of Chelidonium majus or Celandine (highly magnified), 

 Bhowlng a netwoA of laticiferous vessels. The direction of the currents in the vessels is 

 indicated toy the arrows. 



Fig. 241. 



