Cholnoky: Cell Structure and Environment 371 



As this exposition is mainly concerned with the efifects of the environment 

 on the structure of the protoplasm, I shall have to omit a detailed description 

 of what is known about the general principles of stain uptake and storage or 

 changes in the stain molecules, e.g., ionization in the cell or its environment. 

 It would also go beyond the scope of this paper to draw attention to the present 

 state of our knowledge derived from investigations with the fluorescence micro- 

 scope. As far as I am aware, those studies have hitherto only been made with 

 material divorced from its natural habitat, and have, in many cases, degen- 

 erated merely into a study of stains, without reference to colloidal structure 

 or the changes it undergoes. Such work often led Biitschli el al., into fruitless 

 hypothetical discussions. 



This scarcely scientific approach is regrettable because even the first experi- 

 ments on stain uptake in algal cells (Cholnoky, 1934, 1935a, 1935&, 1935c) 

 showed that uptake and storage of the stain molecules, or the ion gradients in 

 the protoplasm was far reachingly dependent on the conditions under which 

 the algae lived before the experiments. When stained with methylene blue or 

 neutral red, the disassociation of the stain molecules remained dependent upon 

 the conditions of the culture before the staining experiments were done. Also 

 in those cases in which the stain fluid (unlike the culture fluid) possessed con- 

 stant physicochemical characteristics {e.g., stains dissolved in distilled water, 

 buffer solutions or plasmolytica) the effects on the protoplasm of increased 

 osmotic pressure, pH, and light conditions could be clearly proved. 



The environmental conditions before the staining experiments generally hav- 

 ing remained neglected; this explains why so many apparently contradictory 

 results were obtained. The use of fluorochromes increased still further the 

 complexity of an already complicated position, as conclusions were drawn re- 

 lating to the storage of stain molecules and ions which incorporated many hypo- 

 thetical assumptions, such as "full" and "empty" ceU-sap (Hofler and Schindler, 

 1955), which did not attempt to reconcile observed facts with the environmental 

 factors under which the algal cells were living before the experiments. 



This change of concept became apparent as preliminary work (Cholnoky and 

 Hofler, 1950) had already been done which went so far as to enable one to dis- 

 tinguish between the cytological behavior of species (Loub, 1951). 



Regarding Loub (1951), it should be remembered that his material came from 

 ecologically dissimilar environments. After arrival in the laboratory they were 

 rough cultured and only examined after a more or less lengthy period. Apart 

 from the fact that the culture conditions were uncontrolled in the rough culture, 

 Loub did not investigate the natural conditions of the habitat. By his method 

 he was able to examine only adapted associations. He thus lost the oppor- 

 tunity to investigate the protoplasmic changes caused by ecological factors. 



It will be clear from what has been said that most protoplasmic experiments 

 (such as plasmolysis and staining) were done without reference to the condi- 

 tions in which the algae lived in nature or in cultures. Although the cytological 

 results obtained are of very great value, it is indispensable that the methods 

 so far used should be thoroughly changed. Ecological studies have shown on 

 the one hand that not only the conditions of life prevaihng at the time of the 

 experiments but also their fluctuations must affect protoplasmic structure. On 

 the other hand, it now seems certain that Naumann's trophic conditions of the 



