WENHAM, ON THE CIRCULATION OF THE SAP, ETC. 277 



moved in the Anacharis, showinii; that the force is the same 

 in both cases. In a hair of the Primrose I watched an octo- 

 hedral crystal of oxalate of lime carried by the current several 

 times from end to end of the cell. By the term ciliary wave 

 it is not intended to imply that individual cilia can be seen. 

 All that can be shown is a waving motion, such as would 

 undoubtedly be attributed to ciliary action if seen in an 

 animal structure. I will not at present attempt to offer any 

 suggestion as to the use of these currents, though they must 

 play an important part in the vegetable cell. Observations 

 made with microscopes of high power and of recent construc- 

 tion are as yet too limited. Other observers will doubtless 

 be led to investigate the subject, and the accumulation of 

 additional facts may lead to a solution of this difficult pro- 

 blem. 



Observations on tlie Circulation of the Sap in the Leaf 

 Cells o/" Anacharis Alsinastrum. By F. H. Wenham. 



There is no known plant in which the sap-rotation has been 

 discovered that displays the phenomena of the circulation 

 more distinctly, or in such variety of detail, as the newly 

 imported water-weed, Anacliaris Alsinastrum. Having ob- 

 served some peculiar features in this, which I have not dis- 

 covered in the circulating sap of any other plant, I venture to 

 announce them. I must, however, premise that I have not 

 made a special study of this department of vegetable physio- 

 logy, and may therefore be excused from drawing ;uiy con- 

 clusions, or for showing a defective acquaintance witli techni- 

 calities ; — I have simply to relate what I have seen. 



Those who are not already familiar with the plant may 

 readily recognise it by its peculiar characteristics : — Its form 

 of growth is in long slender stems, which bear a series of 

 three narrow leaves, of a pale-green colour, at intervals of 



Fig. 1. 



::> ^« w -^ -^ ^ 



about a quarter of an inch asunder ; these, when full grown, 

 seldom exceed a length of three-eighths of an inch (see fig. 1). 



