I 88 R. R. BENS LEY. 



which thus would have a variable structure from moment to 

 moment in the cell. He claims that the reticular apparatus 

 arises by the appearance in the cell protoplasm of granules or 

 droplets which arrange themselves in net-like or tortuous n>\\- 

 which fuse to form more continuous fibers, and further, that the 

 network so formed can undergo vital changes, by virtue of which 

 it loses its stainability and becomes dissolved, the canals so 

 formed finally disappearing by absorption of their contents. 



In view of the almost universal occurrence of these structures 

 in all of the tissue cells of mammals, and in many of those of 

 lower vertebrates and invertebrates, it seemed probable that 

 they would not be wholly absent from the cells of the other great 

 division of living organisms, namely from the cells of plants. 

 Accordingly, I have studied with this end in view the structure 

 of certain plant cells, using for this purpose in addition to the 

 conventional methods of plant histology, those methods which 

 in my experience were best for demonstration of the canalicular 

 system in animal cells. It seemed probable, in view of the con- 

 ditions found in the animal cell, that, if a homologue of the canal 

 network of the animal cell were to be found in plant cells, it 

 would be studied with greatest ease in those plant cells in which 

 the vacuolar system had not yet reached its full development, 

 namely in meristem tissues, sporogenous tissues and their prod- 

 ucts, cambium and embryonic tissues. The three last, however, 

 did not lend themselves readily to this investigation because 

 of the difficulty introduced by the slow penetration of the fixing 

 agents, so that I have been obliged for the present to content 

 myself with the results obtained in the root-tips of AUiuni. 

 Lilinm and Iris, and in the tapetum of the lily. Whether tin- 

 consistent results obtained from the study of these cells are 

 generally applicable or not to plant cells, future investigation 

 will show. In the meantime, because of the fact that the result - 

 are at variance with the accepted views of the structure of tin 

 cells in question, because they furnish a new interpretation <>t 

 the history of the vacuole of these cells and in particular because 

 they seem to throw an interesting light on the question of de- 

 nature of the canalicular apparatus of animal cells, it seem- \\i-<- 

 to put these preliminary observations on record. 



