CIRCULATION IN PLANTS. 49 



by the presence of a great number of minute 

 globules, visible with the microscope. The vessels 

 in which these fluids are contained are of a pe- 

 culiar kind, and exhibit ramifications and junc- 

 tions, resembling those of the blood vessels of 

 animals. We may also discover, by the aid of 

 the microscope, that the fluids contained in these 

 vessels are moving in currents with considerable 

 rapidity, as appears from the visible motions of 

 their globules ; and they present therefore a re- 

 markable analogy with the circulation of the 

 blood in some of the inferior tribes of animals. 

 This curious phenomenon was first observed in 

 the Chelidonium by Schultz, in the year 1820 ; 

 and he designated it by the term Cyclosis, in 

 order to distinguish it from a real circulation, if, 

 on farther inquiry, it should be found not to be 

 entitled to the latter appellation.* 



The circular movements, which have been 

 thus observed in the milky juices of plants, have 

 lately attracted much attention among botanists: 

 but considerable doubt still prevails whether these 

 appearances afford sufficient evidence of the 

 existence of a general circulation of nutrient 

 juices in the vegetable systems of those plants 

 which exhibit them ; for it would appear that in 

 reality the observed motions of the fluid, are, in 

 every case, partial, and the extent of the circuit 



* " Die Natur der lebendigen Pflanze." See also Annales 

 des Sciences Naturelies, xxiii, 75. 

 VOL. II. E 



