18 PRACTICAL HISTOLOGY [ll 



The white corpuscles and platelets will be stained a light lake red, 

 and their outline will not be very distinct. 



14. Staining a film with eosin and methylene blue. 

 Add to the bottles used in 13, two, one containing a 

 saturated solution of methylene blue in 75 p.c. alcohol, 

 the other 75 p.c. alcohol. Proceed as in 13, but after 

 the cover-slip has been placed in the second alcohol 

 hold it for 20 seconds in the methylene blue, dip it (half 

 a second) in the 75 p.c. alcohol, then without delay 

 press lightly between the blotting pads, dry and mount. 

 The nuclei of the various cells will be stained blue. 

 Note 



a. The shape of the nuclei of the white corpuscles 

 ( 5, a), and the bright red stain of the granules of the 

 coarsely granular cells. 



Some of the hyaline cells will probably have fragmented 

 nuclei ; the cell-substance has usually a faint brownish red 

 stain. 



6. The finely granular basophil cells; these 

 consist of a small amount of cell-substance, containing 

 small granules stained deep blue, and of a round feebly 

 stained nucleus. A few only are present in blood free 

 from lymph. 



c. The swollen and partially disintegrated platelets ; both 

 cell-substance and nucleus (probably round) have a feeble blue 

 stain, and the two may be indistinguishable. Some may be 

 preserved in their normal form, in which case they take a fairly 

 deep stain. 



The corpuscles may be fixed before staining by one of the 

 methods given in Lesson in. for human blood. 



15. Platelets. Mount a small drop of blood 

 direct from the blood vessels or from the heart (cp. 1). 



