220 PHASE MICROSCOPY IN BIOLOGY AND MEDICINE 



Zinser (1947) recommends phase microscopy for the diagnosis of 

 trichomonas in fresh moimts of vaginal secretion. FertiUty problems 

 involving sperm are aided by information obtained with the phase 

 microscope (Farris, 1948, 1950). 



Many parasites such as fungus mycelium in skin scrapings, 

 irypanosomcs, and other organisms, can be seen to advantage Avith the 

 phase microscope. Large unencysted forms, like B. coli, show better 

 with low bright contrast, and smaller ones with medium or high con- 

 trast. The sporozoites of malaria can be seen in the stomach of the 

 moscjuito Aedes cgypii with a medium bright A+ contrast phase oil 

 immersion objective (Fig. V.IOE'), and trophozoites show in human 

 blood smears (Fig. \.\QF), with this and with the dark-contrast 

 objectives (Richards, 1947). Endamoeha histolytica and Endolimax 

 nayia can be seen with low contrast Adz diffraction plates although the 

 protoplasm of the parasitic forms is denser and they do not show as 

 well as free living Protozoa. Encysted forms are more easily found with 

 the 2.5B-0.4X dark and the 0.07A+0.25X bright contrasts, and for 

 some of these the A— dark contrast is unsatisfactory (Fig. V.IO, 

 A and D). 



The phase microscope was used early by Albertini (1946-1948) for 

 the investigation of tumors. He even devised a suitable mounting fluid 

 for the study of cells from tumors (Section 3.2 of Chapter IV) and 

 reported that the same details could be seen in the unstained living cells 

 with phase as after staining with brightfield microscopy. In addition 

 fresh material was preferred for diagnostic procedures. Cells were 

 found in body fluids and exudates. Albertini described dedifferentia- 

 tion, disorganization and regenerative processes. 



Oliver et al. (1947) and Paff et al. (1947) examined tumor scrapings 

 and tissue cultures of tumor materials. With the phase microscope 

 granules could be followed in the living cells which they believe are 

 concerned with heparin formation. The material came from a spon- 

 taneous mast cell tumor in a dog. The same granules were seen in 

 tissue cultures from such tumors. 



Zollinger (1948a) compared findings with lirightfield and phase 

 microscopy and began a series of studies on normal and atypical tissues. 

 Blister formation, called potocytolysis, was reported along with observa- 

 tions on the cell membrane (Zollinger, 19486). The effects of fixing 

 agents and other chemicals were tested on resting and di\'iding cells. 

 Formalin, acids, alcohol, and acetone caused the nucleus to appear 

 brilliant (more refractile), whereas alkali, M NaCl, and distilled water 

 turned it hazy. The nuclear membrane was thought not to be dissolved 

 during mitosis. In another paper Zollinger (,1948e) investigates 



