PLATE XXXIII 

 Azotohacter chroococcum 



Fig. I. — Photomicrograph of a 65-hour-old cultiire stained by the Guignard method. 



Fig. 2, 3.— Photomicrograph of a 65-hour-old cultiire stained by the Heidenhain 

 method. 



Fig. 4. — Photomicrograph of a 2-day -old culture stained with methylene blue, i 

 to 1,000. 



