I the pith cells of Saururus cernuus. 401 



all motion has ceased, in such cases the granules are alwaj^s 

 closely crowded together in the centre of the cell. 



The time during which this motion continues is quite remark- 

 able. Specimens of the plant kept for several dajs in water 

 never fail to show it, while the proper pith cells of all parts of 

 the plant, even of the blanched portions of the stem growing 

 Indeed no form of c^cZo- 

 so easily demonstrated. 



The nature of the granules however is not so readily deter- 

 mined, for they do not show the starch reaction with tincture of 

 iodine, neither are they colored as proteine compounds, (and 

 such I had at first supposed them to be,) would be under this 

 reagent. There is however a remarkable difficulty, common also 

 to many others, in applying chemical tests to sections of this 

 plant, and this consists in the rapid discoloration of the speci- 

 mens, owing to the presence of tannic acid which acts upon the 

 iron of the cutting instrument. It is quite certain however that 

 the granules are neither starch nor proteine, whether they are, 

 the so-called, aleurone, I am unable to say. 



To those familiar with the microscopic examination of fresh- 

 water algse, this "swarming" apart from the best known case of 

 the Closterium, must be quite familiar— but such motions have 

 always been considered as in some way connected with sexual 

 reproduction. In the case in question however nothing of the 

 kind can possibly occur— for the Saururus is, beyond a doubt, 

 not onlv a phsenogamous, but even a dicotyledonous plant, 

 closely allied to the Pepper family. The cells m which this mo- 

 tion is seen are evidently smaller and younger than those in 

 their immediate vicinity. Sometimes indeed two vertical rows 

 of small cells show the same motion. The phenomenon in ques- 

 tion would therefore merelv indicate active cell muUiplicaiion and 

 not plant reproduction, to which similar appearances have always 

 been referred. AVith a somewhat extensive experience I am 

 able to say that nothing of the kind has before been observed m 

 phfenogamous plants; yet it must be admitted that one single 

 instance among them is sufficient to invalidate the inferences for- 

 merly drawn from algae, as to the true meaning of this peculiar 

 kind of motion. 



I am more earnestly disposed to insist upon this, apparently, 

 exceptional case because it confirms views long held and taught 

 by myself as to the purely physico-chemical mterpretation of 

 most of the phenomena of vegetable life. 



