156 Autonomy of Cell-Organs 



of water, one can bring about at will this hardening in the 

 still liquid cell-sap, and in this way artificially produce the 

 formation of aleuron-grains under his very eyes. 



It is important that, in some seeds more, in others 

 less, the vacuoles divide during the process of ripening 

 into several smaller, frequently into very numerous ex- 

 tremely minute vesicles, which gradually fuse again into 

 one large vacuole at the beginning of germination. 



The processes in the seed, therefore, fit beautifully 

 into the conception that the vacuoles originate only by 

 division. 58 



Just as the chromatophores can differentiate into the 

 most various organs, so also can the vacuoles, although 

 to a lesser extent. Went observed how, in different cells, 

 there lie vacuoles which remain separated throughout 

 their existence, and are distinguished by their different 

 contents. 59 Frequently some of them are stained, others 

 are colorless, or some contain tannin, which is lacking in 

 others. In such cases the latter are called by that author 

 adventitious vacuoles. 



The contractile or pulsating vacuoles form a special 

 system. In the swarm-spores of the algae they probably 

 originate from the other vacuoles 60 through further dif- 

 ferentiation, but in the Euglense, according to the investi- 



58 In Miiller's bodies of the ant-plant, Cecropia adenopus, Schim- 

 per illustrates formations in the cell-contents which, at first glance, 

 look like vacuoles, and which, on account of their semi-fluid con- 

 tents, he compares with the aleuron-grains. Their origination from 

 vacuoles can hardly be doubted. Schimper, A. F. W. Die Wechsel- 

 beziehungen zivischen Pfianzen und Ameisen. 1888. Cf. especially 

 Taf. II, Fig. 11. Also Wakker, Jahrb. Wiss. Bot. 19: 467. 1888. 



59 Went. loc. cit. pp. 65-91. 



60 Or have the turgor-vacuoles possibly originated phylogenetically 

 from the pulsating ones? 



