370 Annals New York Academy of Sciences 



characterized if the cytomorphological changes which they caused could be 

 compared with the poisonous effects of other substances. For this purpose 

 cuhures were utiUzed of which the culture fluids were displaced by cocaine and 

 colchicine, both of which are known to be cell toxic to a high degree. The 

 effect of cocaine on Cladophora (Cholnoky, 1930a) showed that this alga was 

 able to tolerate appreciable concentrations and that it can react in a very 

 characteristic manner. Without any microscopically visible protoplasmatic 

 changes occurring, resting stages developed, which were independent of the 

 seasons, and appeared to be completely resistant to cocaine so that when re- 

 moved to a normal habitat {i.e., cocaine free) they were able to germinate. 

 That these observations remained comparatively unknown, may be due to the 

 title of the paper having been arbitrarily changed by the editor of the journal 

 to which the paper was sent. The observations made may explain how algae 

 are able to survive temporary poisoning, as a result, for example, of industrial 

 effluents. 



As is well known, colchicine affects the development of the spindle during 

 nuclear division and is, therefore, often used for obtaining polyploids. This 

 substance was also used for culture experiments. Surprisingly, only a high 

 concentration of colchicine (10 ppm) resulted in damage to the nuclear division, 

 but no polyploids were obtained. With Cladophora the number of nuclei in 

 the polyenergid cells was reduced. With Spirogyra, etc. pseudosexual condi- 

 tions quickly developed which often became lethal after only a lapse of several 

 weeks. The observed phenomena may explain why certain industrial wastes 

 produce no poisoning of the cocaine type (certain cells become impermeable to 

 poisons), but many abnormalities instead. The results of this series of experi- 

 ments were also entirely lost owing to the war, and as no further opportunity 

 to repeat them has been given me, it is up to some other researcher to undertake 

 this work. Nevertheless, they do seem to elucidate the effects of the waste 

 products produced by human activities as far as the terms "pollution" and 

 "poisoning" of natural waters are concerned. 



I am familiar with only a few of the cytological effects of other poisons: 

 among these are the studies on aluminium salts and "cramp" plasmolysis 

 (Weber, 1924, 1933; Hofler, 1958) which clearly show that the salts have ren- 

 dered impossible the functions of the investigated cells through colloidal 

 changes etc., and very probably also through interference with the electrical 

 charge of the micelles. Although the quoted papers do not mention the colloid- 

 physical significance of the phenomena, it seems to me that they must be due 

 to coacervation and coagulation. 



Colchicine as well as cocaine cause radical changes in the structure of the 

 protoplasm which are to a certain extent discernible by experiment, but the 

 mechanism of the effects of poisoning can be better seen microscopically if the 

 poisons can be seen or can be made to be seen. When the first algal investiga- 

 tions were started, the results of the experiments which had been made with 

 the cells of the higher plants led one to suspect that the process known to the 

 workers during the classical period of cytology as vital staining was actually 

 a microscopical manifestation of poisoning and destruction of the cells. It was, 

 therefore, possible without further ado to use stains which were formerly re- 

 garded as harmless, i.e., which did not kill the protoplasm suddenly. 



