BACTERIA, PHAGE, AND VIRUS 201 



and Kappel (1949) found blue light and high-aperture phase objectives 

 useful with gonococci. 



A preparation of Aerohacter in glycerin jelly suggested the presence of a 

 capsule, but the difference in optical path was not adequate for certain 

 observation. A pneumococcus provided through the courtesy of Dr. 

 Erwin Neter had good capsules, and the ad^'antage of the phase micro- 

 scope for observing these unstained living organisms in aqueous mounts 

 is apparent when L, A^, and of Fig. ^M are compared with M. Two 

 cells, N and of Fig. V.l, have been interpreted as either simple fission 

 or as a possible reduction stage in sexual reproduction. Continuous 

 observation or motion picture recording should answer such questions. 



Swimming bacilli often show an undulating movement tliat Pijper 

 has described and photographed with solar darkfield cinephoto- 

 micrography. Pijper (1949) reports seeing fiagella on a large spirochete 

 with phase microscopy. High-speed pictures of profeus and subtilis by 

 Richards did not show fiagella, nor did he see them in normal swimming. 

 The addition of some Alethocell to give a more viscous medium did 

 suggest twirls similar to those seen by Pijper. Further study with both 

 methods should pro^'ide the information needed to understand the 

 motility of bacteria. The meagerness of information available and the 

 details shown in the figures demonstrate the possibilities of phase 

 microscopy in these fields. 



Unstained fixed Rickettsiae may be seen with the 0.14A-f-0.25X and 

 the IB— 0.25X diffraction plates, and the latter makes them even more 

 visible when stained with the Machiavelli stain. The higher contrast 

 may be preferable for the examination of small living organisms. 



The action of the bacteriophage on Rhizobium was observed and 

 reported by Hofer and Kichards (1945). The ability to follow the 

 changes in lysis in the li\'ing organisms assisted in understanding the 

 process even though the resolution of the light microscope was not 

 adequate for all the details on the phage. Barer (1948a) reported 

 seeing the virus of psittacosis and of vaccinia. Inclusion bodies in 

 unstained tissue sections of yellow fever (Fig. V 3, A^ and 0), herpes 

 simplex, fowl pox, and distemper were reported by Angulo et al. (1949), 

 who found the 0.14A-f0.25X bi-ight contrast most useful. They 

 discussed the importance of phase microscopy for studies on the struc- 

 ture of inclusion bodies and the diagnosis of virus disease. Viral 

 inclusion bodies have been seen in tissues from diseases of undetermined 

 etiology (Angulo, 1949a). Another paper discusses inclusion bodies of 

 rabies, vaccinia, wheat mosaic, j^ellow bean mosaic, mengiofeline- and 

 mouse pneumonitis, and trachoma (Angulo, 19496). Slumps virus has 

 been seen with a high bright-contrast phase objective. 



