218 LILT H. HUIE. 



both dry and wetted with distilled water; the former proved 

 most active. In about 15 per cent, of the leaves used some of 

 the tentacles bent slowly, taking about twenty-four hours to 

 close ; but as a rule the tentacles did not move at all, though 

 their secretory activity appeared to be stimulated. Some of 

 the leucin was dissolved and hung from the leaves in large 

 drops, which finally fell off. In some cases it was not dis- 

 solved, and fell off or was blown away. In any case the ten- 

 tacles were to all appearance left quite uninjured. 



Leaves were fixed at the following intervals after feeding : — 

 Five minutes, one hour, one day, two days, three days. 



The cytological changes seem to be produced very tardily. 

 I find none during the first two periods. After one day there 

 is considerable vacuolation of cell plasm and nuclear plasm, 

 and slight diminution of nucleolus. In tentacles that had 

 closed there is slight but quite distinct increase of chromatin 

 three days after feeding (fig. 25). This has not been seen to 

 occur in tentacles which remained unbent. 



Urea did not adhere to fixed material, and so does not 

 appear in the stained preparations. 



Crystals were powdered, and dusted on the tentacles. The 

 urea readily melted in the secretion, and seemed to increase 

 the exudation, but caused no bending of the tentacles. At the 

 end of half an hour the leaves looked as if they had been 

 under a shower of rain. In twenty. four hours the leaves 

 appeared yellow, flaccid, with weak and shrivelled tentacles. 

 Death of the leaf invariably ensued. 



One Hour after Feeding (fig. 26). — The cell walls are 

 blue. The cytoplasm is still blue and granular in the lower 

 half of the cells, but is vacuolated in the upper half. The 

 nuclear membrane remains irregularly distended, but the 

 nuclear contents have contracted to form a small dark 

 purple body in the centre of the nuclear cavity, in which 

 neither nuclear plasm, chromosomes, nor nucleolus can be 

 distinguished. 



One to Two Days after Feeding (fig. 27).— The 

 withered tentacles show the cytoplasm reduced to a scanty 



