TRANSACTIONS OF SECTION K. 861 



Canada balsam. Petals of Iris, Vetch, or blue Linum, Sec, do not give the same 

 results. The coloured sap escapes from the cell as soon as the protoplast is killed. 

 In Tradescantia it cannot escape so rapidly, owing apparently to the presence of a 

 cuticularised membrane around each cell, and it consequently remains in contact 

 with the nucleus a sufficiently long time to stain it. By means of this cuticular- 

 ised membrane the penetration of fixing fluid appears to be to some extent pre- 

 vented. The resistance of the cells to the action of reagents is, however, very 

 variable. In methylated spirit the protoplasmic movement ceases in most cells at 

 the end of 1^ minute, but was still observable in a few cells at the end of 2f 

 minutes. In 3 minutes a large number of the nuclei had become stained blue. 

 In 70 per cent, alcohol protoplasmic movement was visible in a few cells at 

 the end of 11 minutes, but was very slow and had ceased altogether in IH minutes. 

 In 70 per cent, alcohol, with a few drops of 5 per cent, solution of hydro- 

 chloric acid, the movement was visible in some of the cells at the end of 7 minutes ; 

 in Pereny's fluid at the end of 17 minutes, but had entirely disappeared in 17^ 

 minutes ; in saturated solution of corrosive sublimate the movement stopped at 

 once (in 15 to 30 seconds) in most cells, but was still visible in a few at the end 

 of 2^ minutes, when it ceased altogether. In a 2 per cent, solution of potassium 

 bichromate movement was observable 4 hours after immersion, and in two other 

 cases for 2i hours ; in one case the hairs were placed in a small bottle of the 

 solution. With a 1 per cent, solution of chromic acid movement was visible 

 li hour after the reagent was placed upon the hairs, and in the case of complete 

 immersion of a few hairs in a bottle, 1 hour 25 minutes after immersion. The 

 colour-changes which take place are : (1) The purple sap turns light blue, then 

 greenish; (2) the nucleus and cytoplasm take up the stain; and finally (3) the 

 colour disappears entirely, leaving only the brownish colour due to the reagent. 

 In a 10 per cent, solution of ammonia the movement continues in some of the 

 cells for 16 minutes. The colour-changes are interesting : (1) the sap first of all 

 becomes light blue, with slow cytoplasmic movement ; (2) dark blue, movement 

 stopped, and coagulation taking place ; (3) green, protoplasmic strands completely 

 broken up, coagulation masses abundant ; (4) bright green, cytoplasmic strands 

 almost completely broken up and disintegrated. The nucleus remains colourless, 

 and when the green colour begins to disappear, it is found at one end or on the side 

 of the cell, surrounded by a thick layer of granules from the cytoplasm. It then 

 begins to swell up, the sap becomes" lighter and lighter in colour, and gradually 

 disappears, and finally there is left in the cell only a colourless mass of disintegrated 

 protoplasm. 



Under normal conditions the flowers of Tradescantia last for one day only. 

 They open early in the morning and begin to close up at night. This is accom- 

 panied by disintegration of the cells of the petals and stamens, which beconie 

 converted into a pulpy mass in the course of about two days. The protoplasm is 

 completely broken up in the majority of the cells, just as in the ammonia solution. 



If, however, staminal hairs be taken from the flower in the middle of the day 

 and placed in water, the disintegration of the cell does not take place for a much 

 longer time, even after the cell is dead. The cells may remain in the living condition 

 for several days. In one of my experiments a fairly brisk protoplasmic niovement 

 was visible in two or three cells twenty-four days after being placed in water. 

 In the dead cells the nucleus is coloured green and remains so for several days. 



Staminal hairs taken from an open flower later in the day (8 p.m.) already 

 showed signs of disintegration, and in the course of two days had become com- 

 pletely disintegrated. 



Hairs completely embedded in a layer of vaseline still showed protoplasmic 

 movements in a few of the cells at the end of six days. In the dead cells the 

 coloured sap could not escape, but the nucleus did not become stained, and in a 

 very short time both it and the cytoplasm had become almost completely dis- 

 integrated. This seems to indicate that possibly the cell-sap plays some part in 

 the rapid protoplasmic disintegration which takes place when the flower is in its 

 pulpy condition. But further experiments are necessary before this can be satis- 

 factorily determined. 



