CYTOLOGICAL CHANGES PEODUCED IN DROSERA. 217 



normal. The cytoplasm is normal as to colour, much vacuo- 

 lated in upper third. The nuclear plasm is reddish purple, 

 aggregated. The chromosomes and nucleolus are unchanged. 



One Hour after Feeding. — The cell walls are pale. 

 The cytoplasm stains blue, and is much vacuolated. The 

 nuclear plasm is reddish purple and aggregated. The chro- 

 mosomes are more prominent than in controls. The nucleolus 

 is duller red and smaller. 



One Day. — The cell walls are colourless or slightly pink. 

 The cytoplasm is very pale blue, extremely scanty, merely 

 lining the cell wall and surrounding the nucleus. The nuclei 

 are often shrunken. The nuclear plasm is almost absent, and 

 stains faintly blue or violet. The chromosomes are more or 

 less enlarged. The nucleolus is dull red and small. Recu- 

 peration is normal. 



In the tentacles which died the cytological appearance was 

 the same as that caused by death from feeding with urea (figs. 

 26 and 27). 



Creatin (fig. 24). — Creatin was employed dry and also 

 wetted with distilled water. The latter proved the better 

 stimulant. The tentacles bent inwards slowly. Secretion 

 was not profuse. Some leaves seemed quite unaff'ected, and 

 their tentacles did not bend. Those that closed reopened in 

 two days, and the white particles of creatin were adhering 

 to their tentacles apparently unaffected. The examination 

 showed conditions as follows : 



One Hour after Feeding. — The cell wall is normal ; the 

 cytoplasm slightly pink, and greatly vacuolated in the upper 

 half of the cell ; the nucleus unaff'ected. 



In the course of the one or two days in which the leaf 

 remains closed the further cytological changes are not great. 



The nuclear plasm diminishes in quantity. The chromo- 

 somes in some cases increase slightly. The nucleolus dimin- 

 ishes to some extent (fig. 24). Recuperation is complete in 

 two to three days. 



Leucin (fig. 25). — Did not adhere to fixed tentacles, and 

 does not appear in stained sections. Leucin was applied 



