AGGREGATION IN THE TENTACLES OF DROSERA. 319 



A few observations were made on the effects of different 

 temperatures ; but on testing the thermometer of my warm 

 stage the graduation was found to be incorrect. I hope to 

 repeat my experiments and also make some observations on 

 electrical stimulation. 



In conclusion, a phenomenon connected with aggregation 

 will be touched upon. My father observed that in Drosera 

 and in certain other plants such as Erica tetralix immersion 

 in solution of carbonate of ammonia causes the chlorophyll 

 bodies to collect into heaps, and, what is more remarkable, 

 these heaps are converted into masses by the coalescence of 

 the bodies. I have unfortunately been unable to attend to this 

 subject and have only cursorily observed this coalescence; but 

 I have frequently noticed the chlorophyll bodies in the cells of 

 a Drosera tentacle collected into heaps, as shown in fig. 

 4. The subject is no doubt worthy of investigation. It is 

 curious that a solution of carbonate of ammonia which is so 

 potent in producing aggregation of the crimson matter in 

 the cells of Drosera should also cause a somewhat similar 

 movement in the chlorophyll bodies ; and that this aggrega- 

 tion of chlorophyll should occur in other plants than Drosera. 

 Sachsi describes the changes in position undergone by chlo- 

 rophyll grains in various unfavorable external circum- 

 stances ; "for instance, in small fragments of tissue, when 

 respiration is defective, turgidity diminished, temperature 

 too low, the cells too old, or — what is of most interest here 

 — where light is cut off for a considerable time." Under 

 these circumstances the chlorophyll bodies collect together 

 in certain positions. Sachs considers it certain that they 

 possess no power of independent movement, and that their 

 change in position is due to the action of the colourless proto- 

 plasm in which they are embedded. 



If this holds good with the chlorophyll bodies which collect 

 together under the influence of carbonate of ammonia, the 

 case might be adduced in favour of the view that the crim- 

 son aggregated masses are in like manner passive and only 

 moved by protoplasm external to themselves. 



Finally, I believe that a fair consideration of the argu- 

 ments for and against my father's view, that the aggre- 

 gated masses consist of protoplasm will incline the inquirer 

 to accept it in preference to any opposing theory. I believe 

 moreover that in this way the physiological significance of 

 the process of aggregation is more likely to be justly de- 

 termined. 



1 'Handbook,' p. 672. 



