

31 



have found that so determined are the globules to perambulate 

 their dens, that no account is made of the obstructions : they 

 continue their wonted march in the diminished space, as if 

 they were doomed for a certain space to walk the earth, no 

 matter how confined the course. 



" It must not be supposed, that under ordinary circumstances 

 the circulation necessarily takes place along the whole course of 

 the cell ; on the contrary, the march will sometimes be confined 

 to a Limited space, and sometimes no less than four or five 

 separate establishments wdl be kept up in the same cell. Mr. 

 Varley has seen, for example, in the chara one long cell, at 

 the summit of which a mass of globules was rotating; others 

 were coursing horizontally round the cell lower down ; another 

 set were inarching elliptically below these; while, from the 

 bottom of the cell, two other currents rose vertically and joined 

 the ellipse. 



" The author has not seen this in the chara, but has witnessed 

 a similar phenomenon in the hairs of the galeopsis. 



" Although a good deal has been spoken of the motion 

 of the chlorophyll, it must not be supposed that no circulation 

 can take place unless it is present in the cells; for not only 

 does it go on, as has been seen, when the globules are sta- 

 tionary, but when none are actually present. For example, 

 the radicles of the valisneria are perfectly white, and contain 

 no green globules whatever, and yet the circulation in them 

 is as regular as in the leaves, if indeed not more so. 



" If the effects of certain re-agents and stimuli upon the 

 circulation in the acpiatic plants are examined, it is found that 

 heat and cold have a very marked effect upon it. It will be 

 remembered, that when the author first exhibited to the 

 Society the phenomenon in the valisneria, the pieces that 

 were brought for examination had their circulation stagnated 

 by the exposure to the frosty air which they had experi- 

 enced ; but that it was recovered again shortly after they had 

 been in (he warm room. In Ihe same way the motions are 



