SYMPOSIUM ON COLLOIDS w 



In protoplasm the multiple vacuolate condition may have 

 another origin as is shown by Bensley (5), in his late work 

 en the canalicular systems of plant and animal cells. He con- 

 cludes wUh the sentence, "I regard, therefore, the canalicular 

 system as the true condition intra vitum of the vacuolar ap- 

 paratus in these cells of the root tip, and believe that the multi- 

 ple vacuole condition is of secondary origin due in most cases 

 to injury of the cell." Here while the origin of the multiple 

 vacuolate condition is different from that found by Hardy in 

 gelatin gells, it is nevertheless a deformation of the prevailing 

 structures. 



In answer to the third question above, Are colloidal struc- 

 tures complex enough to satisfy the demands of protoplasmic 

 processes? it should be stated that many reactions are occur- 

 ring in a cell coincidently — reactions of 'the most diverse char- 

 acter and of antagonistic types. On this basis Hofmeister (6) 

 believed there must be a special structure offering compart- 

 ments separated by membranes of special permeability char- 

 acters to isolate and regulate these reactions. This he thought 

 doubly necessary for cells with few special organs. The foam 

 structure of protoplasm cares amply for this chemical neces- 

 sity, especially if the walls of the foam are endowed with per- 

 meable qualities varying with conditions and with location in 

 the cell. 



Some of the students holding to the more strictly colloidal 

 conception offer a number of arguments against this view. 

 Protoplasmic movements argue against such a structure. The 

 ultramicroscope generally fails to reveal foam structure in 

 gels and sols in vitro as well as in the protoplasm. Such struc 

 tures are apparently not ever present, but are formed as a result 

 of certain accompanying conditions. 



As our intra vitum staining methods improve and as new 

 methods of the direct study of the living protoplasm are de- 

 veloped, such as the dissecting method of Kite, we are finding 

 more and more bodies of micronic size in the cell. These are 

 included under a variety of names such as mitachondria, chon- 

 driasomes, etc. If we remember that colloidal particles of this 

 nature generally surround themselves with special membranes, 

 which give them peculiar permeability characters, it is easy to 

 see that here again is the possibility of the isolation and reg- 

 ulation of chemical reactions. Aside from these the ordinary 

 plant cell has plastids, vacuoles, or canalicular systems and 

 nuclei. 



