222 PHASE MICROSCOPY IN BIOLOGY AND MEDICINE 



cytology of dying and dead cells, especially with respect to the nuclear 

 changes. Cole (1948) discussed the value of the phase microscope in 

 the investigation of the osteopathic lesion. Flotation methods are 

 described by Fawcett et al. (1950) for separating malignant cells from 

 blood and serous fluids. 



Larger tiunor cells and cytoplasmic detail are seen best with 

 0.35A±0.25X to 0.2A±0.25X, smaller cells and nucleoli with 

 0.2-0.14A±0.25X, mitochondria with 0.07A+0.25X, and small gran- 

 ules with 0.2A+0.1X diffraction plates. 



Leprosy bacteria from treated cases appear different from those from 

 florid cases, and aggregations of bacteria in globi are described by 

 Richards and Wade (1949). Phase microscopy in hematology was 

 discussed in Section 4 of this chapter. Its application in pathological 

 cytology is promising as demonstrated by Dustin (1949) for pycnonecrosis 

 or nuclear destruction studies, as well as in showing changes from 

 irradiation and radiomimetic poisons. The pathologist can examine 

 small cellular granulations, especially with the B — dark-contrast phase 

 objectives, and can often distinguish autolysis from degeneration. 



Thus, the use of the phase microscope in investigative medicine 

 promises the development of improved methods that will become routine 

 in clinical, forensic, and laboratory medicine.* 



* Dustin (1949, p. 84) has also predicted: "II nous parait que la microscope de 

 phase deviendra un outil d'utilization courante, taut dans la recherche qu'en prac- 

 tique medicale." 



