102 THE BACTERIAL PHOTOCHEMICAL APPARATUS 



Fig. 11. Preparation of pigmented membrane fraction isolated from a 

 large Chromatium (strain Tassajara) negatively stained with phos- 

 photungstate. X 180,000. 



Fig. 12. Thin section of pigmented membrane fraction isolated from 

 R. ruhrum grown photosynthetically at 50 foot-candles. Main fixation 

 2 hours, post staining with lead hydroxide. X 180,000. 



