166 THE PHENOMENON OF 



become broken up irregularly; we see them fall in, tear 

 up, and separate into little amorphous masses. From this 

 solution the contents soon gather up into anew structure; 

 the irregular green pieces become rounded, and take the 

 shape of regular, accurately defined globules, of which 

 two or three times as many are produced in each parent- 

 cell, as there were previously chlorophyll zones present in 

 it. In the first period after their origin, these balls, 

 developing into seed-cells, exhibit a weak vibratory or 

 revolving motion, but they soon come to rest, and become 

 enclosed in a smooth, colourless cell-membrane, which, 

 however, is shortly afterwards peeled off again, and 

 replaced by a second, rough and papillose cell-membrane 

 of considerable thickness.* The originally green colour 

 of the contents is gradually changed into a brownish, 

 brownish-violet or, in other species, bright red-lead colour. 

 Nageli has observed in Bryopsis Balbisiana and other 

 Algae, f an abnormal formation of free cells out of the 

 broken-up cell-contents of old cells, not unlike the normal 

 formation of the seed-cells of Sphceroplea ; these observa- 

 tions also confirm the secondary formation of the cell- 

 membrane on the surface of portions of contents already 

 individualised, i. e. shaped out into cells. With the last- 

 named phenomena may be associated the processes of 

 reorganisation, also observed by Nageli, in injured and 

 partially decaying cells, f which show that the surface of 

 contents retracted from the cell-membrane by partial 

 disturbance, clothes itself anew with membrane by con- 

 tinuous secretion of cellulose, and indeed that the healthy 

 portion of the cell-contents has the power of cutting itself 



* Kiitzing ascribes to the spores of a Sphceroplea an outer coat formed 

 of a filiform structure wound spirally round the inner membrane, which 

 doubtless depends on a misconception. 



f Vide Nageli, 'Ueber freie Zellbildung,' 1. c., 24-26, t. iii, f. 1-3. (Transl. 

 in Ray Society's publications, 1849, pp. 96-98, t. ii, f. 1-3.) 



J Vide Nageli, ' Wandstand. Zellbildung,' &c. ' Zeitschr./ 1844, 

 p. 91-95, t. i, fig. 8, 11, 12. (Transl. in Ray Society's publications, 1845, 

 pp. 268-71, pi. vii, figs. 8, 11, 12.) 



