336 CYCLOSIS, OR MOTIONS IN LATEX. [BOOK n. 



transparency and slight thickness is not very easily seen. 

 Likewise in Chara it is not, as is generally supposed, the cell- 

 sap itself which moves, but a denser fluid present in large 

 quantity and occupying the outer parts of the cell- cavity, as 

 has been already shown by other observers." (Annals of 

 Natural History, 18. 6.) 



Of Cyclosis. 



In the first volume, a particular kind of tissue, called cinen- 

 chym, or vessels of the latex, has been mentioned. It is in 

 this description of tissue that the phenomenon of what is 

 called cyclosis takes place. The detailed statements of 

 Professor Schultz of Berlin, from whom, almost exclusively, 

 the description of this phenomenon has originated, are as 

 follows : 



1. The phenomenon of cyclosis consists of a motion of fluid 

 called latex, usually more or less milky, but often transparent, 

 which conveys granular matter through a plexus of reticu- 

 lated vessels, in all directions ; when the vessels are parallel 

 and near each other, the currents rise in some and fall in 

 others, but, in connecting or lateral vessels, the currents are 

 directed from right to left, or the reverse, according to no 

 apparent rule. The contiguous rows of vessels anastomose 

 from place to place ; which produces a permanent interrup- 

 tion of the rising and falling currents. In order to enable a 

 circulating motion to take place, it is necessary that the 

 system of vessels should be reticulated, as takes place in the 

 peripherical vascular system of animals. The vessels con- 

 tract and become so small as to be invisible, they then fill 

 themselves again, enlarge, and re-establish the communica- 

 tion which had been interrupted. It often happens that 

 when strong currents are formed, the weak ones disappear. 

 If a current is about to stop, it may be seen to oscillate a 

 moment both in front and rear. If the globules are amassed 

 in a particular place, an obstruction takes place, and the 

 fluid part of the latex is no longer capable of passing along. 

 If we take a thin slice of bark, or better still, certain entire 

 organs, very thin, transparent, and young, but fully formed, 

 in which the latex has an abundance of globules, it is often 



