CYTO-DIAGNOSIS 2QI 



When the fluid has coagulated, put it in a strong bottle 

 with some glass beads or balls, or fragments of glass of 

 any sort, and shake for ten minutes. This will break up the 

 coagulum and set most of the cells free. Allow the fluid to 

 stand for a minute or two so that the pieces of fibrin may 

 settle; then decant the supernatant fluid into the centri- 

 fugalizing or sedimenting tube, and proceed as before. This 

 process is not altogether satisfactory, and it is better in all 

 cases to mix the fluid to be examined, at the time of with- 

 drawal, with a small amount of (roughly) 5 per cent, sodium 

 citrate, which prevents subsequent clotting. 



Where the fluid is pus no preparation is usually necessary. 

 If it clots it does so very feebly, and in this case a little stirring 

 with a platinum loop will set free plenty of cells for examina- 

 tion, or you may take up the clot with a loop and rub it on the 

 slide or cover-glass. 



METHOD OF PREPARING THE SPECIMEN FOR EXAMINATION. 

 The specimens may be examined wet or dry. In most cases 

 the former method is best, as it is quicker, and often yields 

 information which cannot be obtained by a dry specimen. The 

 preparations, however, do not keep, and where permanent 

 ones are required the method is inapplicable. 



Wet Method. Place one drop of watery methylene blue or 

 borax methylene blue on a slide and add two or three drops 

 of the emulsion of cells. Stir with the platinum loop or 

 needle, allow the mixture to stand for two or three minutes, 

 and then apply a cover-glass. The cover-glass may be 

 cemented to the slide by means of melted paraffin applied with 

 a hot iron rod; it is best to do this if the oil-immersion lens 

 is to be used, otherwise the suction of the lens may lift up 

 -the cover-glass. 



Or, put two or three drops of the emulsion on a slide, cover, 

 and examine without staining. Then put a drop or two of 

 acid methylene blue (see p. 31) on the slide just touching the 

 cover-glass; it will pass in by capillarity, and at different dis- 

 tances from the edge you will get an unstained area, an area 

 where the stain is faint, but very selective, and a deeply 

 stained area. The middle zone is best to examine. The red 

 corpuscles, if present, will be dissolved by the acid, and after 

 a few minutes the cells will be stained with great distinctness. 



Dry Meth o d Prepare films on the slide or cover-glass 



