GuilHermond - Atkinson 



— 216 — 



Cytoplasm 



possible to demonstrate but is proved without a doubt in the case 

 of the plastids which appear to be only a special category of chon- 

 driosomes, and furnish an important though indirect argument in 

 favor of this opinion. 



The chondriosomes are visible in living material in which they 

 appear as slightly refractive elements whose forms are exactly like 

 those obtained in fixed preparations. They are more difficult to 





m 



\* • * * * I 



m 



m 



J®- 



1 



B 



Fig. 149. — Diagram of the development of the 

 chondriome in Phanerogams. A, plastids. B, genuine 

 chondriosomes. I, stem and leaves. II, root. A, 

 starch. 



distinguish under the ultramicroscope, for they appear in black 

 with a faintly luminous contour which seems to indicate that, like 

 the cytoplasm, they are in the state of a hydrogel or of a coacervate. 

 The chondriosomes are slowly displaced by the cytoplasmic cur- 

 rents and constantly change shape (Figs. 70, 150), which proves 

 that they are composed of a semi-fluid and very plastic substance. 

 They have a specific weight rather close to that of the cytoplasm 



