iv] GREEN CELLS OF CONVOLUTA 121 



sis, it was evident at once that they represented a 

 stage in the life history of the infecting organism. 



Fig. 19. Egg-capsule of Convoluta roscoffensis occupied by a dark 

 mass consisting of vast numbers of the "infecting organism." 

 (Magnified forty times.) 



The final proof was applied. To the vessel contain- 

 ing colourless, uninfected Convolutas, some of the 

 free, green cells were added. Within two days all 



K ^ :: ~ - v 8 : vv ^^jgf m 3 



/-'-:. ;'-;. .- ' ' ' vT- Y ^>%>tt--'\ r 1 ) 



A :; .;..^/ - ..J '. ~^\-K'2&ffi$&& (=) 



* . ' 



"Vx- 



.. ' ' 



;'>- ^ 



J'-iP ^,x A 



^ 9V Q> /O^AQd7 Q . 



Fig. 20. The capsule shown in Fig. 19 enlarged and compressed 

 during microscopic examination: the "infecting organism" 

 escaping. 



