98 ON THE PLANT-CELL. 



farther superstructure. I myself always prefer as much as possible 

 to refrain from this play of an active fancy, rather acknowledging my 

 ignorance, and endeavouring to show that it arises inevitably from the 

 nature of the thing itself. As in every thing else, however, theoretical 

 views of one sort or another have abounded respecting the phenomena in 

 question. 



In the first place, we are not even acquainted with the morphological 

 significance of the organs in which the delicate cells, with spiral fila- 

 ments, are developed. We know just as little about the development of 

 the cells; are just as, or perhaps more, ignorant regarding the formation 

 of the spiral filaments ; and with respect to their chemical nature, we are 

 able to arrive at only a very imperfect probability. As to the mechanism 

 of the motion, we know just as little as we do of that of the moving cilia : 

 of the cause of motion, of the motive power, just as much as that of 

 the contraction of the primitive muscular fibre, of the motion of animal 

 spermatic filaments, and of the vibratile cilia on animal and vegetable 

 cells ; that is to say, absolutely nothing. A comparison of this motion 

 with that of the heavenly bodies, is, however, wholly inadmissible, be- 

 cause the commencement of the motion in the organisms in question has 

 relation to time, but not so that of the heavenly bodies ; on which ac- 

 count, with respect to the latter, the question after the first impulse 

 (tangential force) does not concern us at all, but it does very materially 

 with respect to the organic structures. All these motions fall into the 

 same category, in every respect, with those which will be described in 

 the following section. Ignorance and stupidity term them " primitive 

 phenomena." The discreet and profound investigator of nature recog- 

 nises their temporary limitation in this respect, as well as their destined 

 application to purposes of further activity. 



43. When a multitude of very minute corpuscles of either an 

 organic or inorganic nature, for instance, minute starch-granules, 

 small crystals, c., are contained in a cell in a fluid of sufficient 

 tenuity, they usually exhibit a quivering motion (termed " mole- 

 cular motion "), the cause of which is still unknown to us ; but in 

 any case it has no necessary or exclusive connexion with the life of 

 the cell. 



Some observations relative to this subject had been made at an earlier 

 period, but had been either disregarded or at least not followed up, and 

 it was not till 1827 that R. Brown* first took up this phenomenon in a 

 connected point of view, and at the same time completed the inquiry so 

 fully, that scarcely any thing remained to be added ; and it required the 

 subjection of a Meyen to preconceived notions to speak of it as a vital 

 phenomenon. 



All bodies sufficiently minute, organic or inorganic, and suspended in a 

 fluid not too thick, present a peculiar oscillatory motion, unattended with 

 any perceptible change of place. Instances of this phenomenon are to 

 be found in almost all plants, in the mucus- and starch -granules, crystals, 

 &c., whether inclosed in a cell or free ; but only when the fluid can 

 retain them in suspension, so that they cannot sink to the bottom. The 

 milky juice, and that contained in the pollen grains, are fluids eminently 

 of this nature, and in these, consequently, the motion in question is most 



* Vermischte Schriften herausg. von Nees v. Esenbcck, vol. iv. p. 143. 



