IRRADIATION OF LIVING PROTOPLASM 



653 



uniform throughout the cell. However, in the application of the centri- 

 fuge method to Spirogyra cells, it must be remembered that the movement 

 of chromatophores presumably depends on the viscosity of the layer of 

 protoplasm directly adjacent to the cell wall (cf. Heilbrunn, 136, page? 

 47, 48). 



From the above, it may be concluded that although the number of 

 workers is not great, their results are thoroughly consistent. The effect 

 of radiation whether of roentgen rays, alpha, beta, or gamma rays, is to 

 cause first a liquefaction, then a stiffening or coagulation. This is 

 evidenced by the data on rate of protoplasmic streaming and more 

 certainly by direct study of viscosity with either Brownian movement or 

 centrifuge methods. 



Fig. 4. — The effect of severe radium treatment on the viscosity of cells of Spirogyra 

 ellipsispora. (a) Control cells. Chromatophores displaced by centrifuging. (b) Cells 

 exposed to beta and gamma rays from RaBr2 preparation of 50 mg. radium equivalents. 

 Chromatophores not displaced by same centrifuge treatment as used on controls. 



The final effect of radiation is to cause a coagulation. All authors 

 are agreed on this except Jansson (177) who found increased Brownian 

 movement in leucocytes following death. It is possible that Jansson 

 may have observed movement of particles in vacuoles, and it should also 

 be noted that an increase in the volume of the cell such as Jansson 

 observed would favor increased amplitude of Brownian movement. 



The coagulation produced by roentgen rays or radium resembles that 

 produced by ultra-violet rays, in that numerous vacuoles are typically 

 produced. Numerous authors have described vacuolization phenomena. 

 These include Nadson and Rochlin (269) on onion scale cells, Jansson 

 (177) on myelocytes, Schubert (336) on chick-heart cells in tissue cultures, 

 Johnson (180) and Komura (193) on plant cells, also Rochlin-Gleich- 

 gewicht on plant material, Gassoul (112, 113) on explants of frog spleen, 

 etc. For other references see Table 5. 



It seems certain that roentgen rays and radium act in the same manner 

 as ultra-violet rays (cf. Nadson and Stern, 271), and it is only logical 

 to assume that any explanation which holds good for ultra-violet would 

 also apply to these other types of radiation. 



In this connection we should like to emphasize the interesting work 

 of Rochlin-Gleichgewicht on the leaf cells of Elodea and Pterygophyllum. 

 In this work a fine emanation needle was placed transversely across the 



