1882.] Protoplasm in the Motile Organs of Leaves. 



273 



must withhold any definite decision upon it. I cannot, however, 

 donbt that protoplasmic continuity is of very frequent occurrence, 

 both in pul vini, stems, roots, and tubers, and I regret that some short 

 time must elapse before I can publish any detailed account of my 

 further researches. 



Since the winter season was rapidly advancing, I instituted other 

 experiments with fresh material, with a view to confirm, if possible, 

 results obtained by strong reagents, whose action was necessarily 

 attended with grave alteration of the tissues. As a consequence of 

 these experiments, some new and important facts bearing on the 

 phenomenon of Plasmolysis have come to light. Hugo de Vries, in his 

 work on cell turgescence, has shown that by treating fresh uninjured 

 cells with progressively stronger and stronger solutions of a neutral 

 salt, e.g., 4 per cent, and 6 per cent, of nitre, the protoplasm 

 (primordial utricle) will undergo more and more contraction, until 

 with a 10 per cent, solution, it will entirely separate from the cell 

 wall, and appear as a much contracted vesicle lying freely in the cell 

 cavity. 



In repeating these experiments I have, however, found that in a 

 very great number of cases — I dare not at present say in all — the 

 contracted primordial utricle is connected to the cell wall by fine 

 strings of protoplasm. The phenomenon is very distinctly shown by 

 the cells of the main pulvinus of Robinia pseudacacia, in which I first 

 made the discovery. Very frequently, instead of there being one 

 main mass connected to the cell wall by the fine threads above-men- 

 tioned, the cell protoplasm becomes divided into two or three 

 globular masses, all of which are united to each other, and to the cell 

 wall. The connecting threads very generally exhibit nodal thicken- 

 ings, each node presenting a most perfect spherical form. 



Since the sections examined must be somewhat thick to avoid 

 cutting into the cells, observations as to the relation of the threads 

 with the pits present some difficulty. However, in several well-defined 

 instances I have seen clearly that many threads do go to pits, and 

 also that in two adjoining cells, many threads on different sides of the 

 common cell wall are exactly opposite one another. When saturated 

 salt solution is added, some of the threads may give way. Each free 

 end immediately contracts: the one to the main mass, and the other 

 to form a minute sphere lying on the side of the cell wall. I have 

 succeeded fairly well in fixing and staining these plasmolytic figures. 



The above plasmolytic phenomena are apparent in ail the pulvini I 

 have examined, e.g., Desmodiuin, Mimosa, Oxalis, Robinia, Amicia, 

 Phoseolus, Apios, &c. I have also observed it in stems and roots, 

 notably in the Beet. 



I should also mention here that I have succeeded in showing the 

 passage of the protoplasm through the cell wall when the wall is 



