CIRCULATION IN PLANTS. 373 



CHAPTER XVI. 



ON THE CIRCULATIOIir IN PLANTS. 



" As long ago as the year 1774 It was known to botanists," 

 says Dr. Lindley,* "that a certain Abbe Corti, of Lucca, 

 had published some remarkable observations upon the circu- 

 lation of fluid in some aquatic plants, and that the accuracy 

 of this statement had been confirmed by Treviranus so far 

 back as the year 1817; nevertheless, the fact does not seem 

 to have attracted general attention until the publication by 

 Amici, the celebrated professor, at Modena, of a memoir 

 in the eighteenth volume of the Transactions of the Italian 

 Society, which was succeeded by another in the nineteenth." 

 The plant employed by all these observers appears to have 

 been a species of Chara, of which genus every species, whether 

 opaque or transparent, will readily exhibit it ; the transparent 

 kinds without any previous preparation, whilst the opaque, 

 from being coated with carbonate of lime, require to have 

 this removed. Since the publication of Amici's papers, the 

 circulation of the sap in various plants, now termed by 

 botanists Cyclosis, has occupied the attention of many indi- 

 viduals In this metropolis ; amongst the most noted may be 

 mentioned the names of Mr. K. H. SoUy, the late Mr. Slack, 

 and Mr. Yarley ; to the latter gentleman we are also Indebted 

 for many valuable discoveries lately published in the second 

 volume of the Transactions of the Microscopical Society, as well 

 as for Important apparatus for viewing the circulation, all of 

 which win here demand our attention. 



Chara. — The plant which Mr. Varley has examined so 

 carefully is the Chara vulgaris, an aquatic plant, found either 

 In stagnant, salt, or fresh water, always submerged, and giving 

 out a most disagreeable fetid odour ; its colour Is green, the 

 stem Is branched and surrounded here and there with whorls 

 of smaller branches, generally nine In number ; a portion of 

 * Vegetable Kingdom, page 28. 



