328 Biological Stains 



cytoplasm; eosinophilic leucocytes, with blue nuclei, red to orange-red granules 

 and blue cytoplasm; basophilic leucocytes, with purple or dark blue nucleus and 

 granules dark purple (almost black); lymphocytes with nuclei dark purple and 

 cytoplasm sky blue; platelets, with violet to purple granules. 



GiEMSA Stain 



Identification: As in the case of Wright stain, no chemical methods for the identi- 

 fication or analysis of this stain have yet been devised. Like Wright stain it is a 

 compound of eosin with methylene blue and its oxidation products. 



Biological Tests: It is tested on dried thin films of blood which have been treated 

 5 to 7 minutes in methyl alcohol. The staining fluid is prepared according to the 

 directions on the label, if such directions are furnished by the manufacturer; 

 otherwise 0.5 g. of the powdered dye is dissolved in 33 ml. glycerin by standing at 

 55-60° C. for 1}^ to 2 hours, then 33 ml. methyl alcohol is added and the solution 

 allowed to stand 24 hours. The dried blood films are immersed in a staining fluid 

 containing 30 drops of the above solution in 30 ml. distilled water. As diflFerent 

 lots of stain vary in rapidity of action it is best to test a sample with three or four 

 slides stained at varying periods from 15 to 40 minutes; it is not condemned if 

 good results are obtained on any one of the slides. Results should be very similar 

 to those secured with a good Wright stain, the chief difference being that the nuclei 

 of the leucocytes are reddish purple instead of a dark violet. 



It is also tested for staining unfixed thick blood films for the diagnosis of malaria. 

 The films are made by spreading 3 to 5 drops of blood over a circle of about 15 mm. 

 diameter on a scrupulously clean slide and air-drying for 18 to 24 hours at room 

 temperature, kept in a horizontal position and protected from dust and insects. 

 The smears are stained in diluted Giemsa stain, as above, or preferably diluted 1-50 

 in distilled water, buffered with phosphates to pH 7.0 or 7.2; they are then washed 

 5-10 minutes in distilled water or buffer solution of the above reaction and air 

 dried. With a satisfactory sample, the malarial parasites should show with clear 

 red chromatin and clear blue cytoplasm, while the red corpuscles do not show on 

 account of the laking of the hemoglobin. 



