RESEAECHES ON PEOTOPLASMIO CONTINUITY. 307 



instances, it certainly appeared to extend from the chlorophyll 

 grain into the general cell protoplasm. 



In order to see whether any abnormal appearances had been 

 brought about by the action of the dilute glycerine, some 

 pieces of the blade were mounted in expressed cell sap and 

 examined. As the thickness of the blade was, however, too 

 great to allow of satisfactory observations being made with 

 high powers, a small piece was teased out before mounting; 

 and since it was found, that during the teasing process and 

 rupture of the tissues, no observable alterations had taken 

 place in the cells, when such a preparation was compared with 

 an uninjured one, in subsequent experiments teased out pre- 

 parations were made use of. 



When such a preparation is mounted in expressed cell sap 

 and examined, it becomes apparent that the outline of each 

 chlorophyll corpuscle is quite defined and distinct, and that 

 little or nothing can be made out of the reticulate structure. 

 I was also quite unable to observe any network in the general 

 cell protoplasm. If, however, dilute glycerine, or simply 

 water, be run under the cover glass, the corpuscles will be 

 seen to gradually swell up, and, in so doing, to display more 

 and more distinctly a reticulate structure. The outline also 

 becomes more and more diffuse, and one almost begins to 

 make out that the network appears to extend beyond the 

 grain into the protoplasm. I am of opinion, however, that this 

 is not the case. 



The structure of the unaltered chlorophyll grain, and the 

 action of reagents upon it, can be much better followed in 

 thin leaves with large grains. I found, for instance, Selagi- 

 nella uncinata very good material. And just as the chloro- 

 phyll grains in uninjured cells of serial plants will swell in 

 the way I have described when treated with water, so will 

 those of water plants when the cell becomes broken into or 

 otherwise injured, e. g. the chlorophyll grains of Char a, 

 Vallisneria, and Elodia. In each case a reticulate appear- 

 ance is first produced, which, upon prolonged treatment, gives 

 way to a granulation, and is followed at length by complete 



