CTTOLOGICAL CHANGES PEODUCED IN DROSEKA. 211 



chromosomes are enlarged. The nucleolus is small and dull 

 red. 



After Two to Four Days. — Recuperation takes place as de- 

 scribed for leaves fed with white of egg, but much more slowly, 

 and is complete in four to seven days. 



Griibler's fibrin-peptone stains red and produces the maxi- 

 mum change in one hour after feeding, as shown in fig. 12. 

 The food appears as pink drops adhering to the outside of the 

 gland. The cell wall is nearly colourless, or faintly greyish 

 blue. The cytoplasm is very scanty. In different leaves it 

 varies in colour from pale blue to pinkish grey. The nuclei 

 are more or less shrunken ; the nuclear plasm reduced to a 

 little granular cloud which stains violet. The chromatin has 

 increased enormously, and forms large segments with rounded 

 ends. Whether their number is constant or not I have not 

 determined. The nucleolus is small and of a dull red tint. 



Milk (stains Blue). — A small drop was placed on the 

 centre of the leaf or drawn over the marginal rows of tentacles. 

 In the first case the leaf itself folded up. In the second case the 

 tentacles closed regularly inwards in ten minutes or less, and 

 after an hour or two the entire leaf doubled over as in the first 

 case. In from one to three days the leaves reopened perfectly 

 uninjured unless the tentacles had been here and there glued 

 together by the milk drying. Milk may be absorbed twice or 

 thrice and the leaf open as clean as a control. 



Five Minutes after Feeding (fig. 13). — The cell walls 

 are somewhat deeper blue than normal. The cytoplasm has 

 contracted into dense strands, appearing coarsely granular and 

 staining a much deeper blue than normal. The nuclear plasm 

 is somewhat redder than in controls, and the individual 

 granules have fused (aggregated) to form dark masses alter- 

 nating with clear spaces. The nuclear chromosomes are 

 normal. The nucleolus appears more of a purple. 



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

 cytoplasm disappears completely except at the periphery of the 

 cell and round the nucleus. It stains pale blue. The nuclei 

 are sometimes slightly shrunken. The nuclear plasm is red- 



