f# 



1 88 



THE BEGINNINGS OF LIFE. 



should understand that the branches of this plant are 

 made up of elongated^ cylindrical^ and transparent 

 cells^ or internodes, of a greenish colour. On micro- 

 scopical examination it has been ascertained that the 

 colour is due to the presence, immediately beneath 

 the cell-wall, of a layer of green chlorophyll disks or 

 vesicles, each of which is about 

 These are uniformly distributed, except along a spirally 

 disposed line — which is therefore colourless — on each 

 side of the cell. In the situation of this line (along 



•^ 30 



in diameter 



which the 



green 



disks are absent), the ^ mucus' or 

 protoplasmic layer has also less depth than it has over 

 other parts of the surface of the internode. The layer 

 of 



reen disks lies, in fact, in the outermost or super- 

 ficial portion of the protoplasmic layer, whilst within 

 this is situated a colourless axial fluid. The inner 

 surface of the protoplasmic layer is irregular and under- 

 goes constant changes of form. It is these contrac- 

 tions of the mucus or protoplasmic layer, taking place 

 in a regular manner, which communicate their motion 

 to the contained fluid, and thus produce the so-called 

 'cyclosis' of the cell-contents. With these explana- 

 tions the reader will readily understand Mr. Carter's 



description 



He 



says : 



'AH are aware that in 



the 



fresh-water Algse commonly called Confervas, the for- 

 mation of the spore is preceded by a breaking up or 

 displacement of the cell contents, after which a con- 

 densation and rearrangement of them takes place, and 

 they are then invested with a capsule which remains 



s of th^ ^^ 



tc 



linnii^o' 



we 



fin 



cessation 



iteefl 



of the c 

 disks formi' 



,iasifobeyIn? 

 enient of the 

 lines which as 



) 



itto 



t am 



the in 



sizes, more or less 



') 



single disks, s 

 in contact with thi 

 Kt stage is the s 



T' 



t groups, 

 and circul 

 ^ fcftain amount 

 cavity of the 



'f'Hreakin^u 



He 



^s transi 

 \ ** We cha„ 



I 



wnish- 



era 



green 



^^y or tv 



^''"^ ^isks be 



J5 this ^ 



