6o6 LABORATORY HINTS 



Leishman's is good and gives them a brownish lint. They are 

 sometimes found in normal blood. Their significance is not known. 



In lymphatic leukc\?mia the leucocytes are irregular in size, shape 

 and staining qualities. Tlie}- are increased to 14,000 per c.mm. 



From 70 to 98 per cent, are lymphocytes. The red cells are 

 diminished in number and hb. 



In spleno-medullary leukcemia, myelocytes are found. The cell 

 may be very large or smaller than normal, the nucleus stains poorly, 

 and it is sometimes studded (U'er with eosinophilic granules. These 

 cells are pathognomonic of this disease. As a rule they are more 

 numerous and larger than any other leucocyte. The nucleus is 

 never horseshoe-shaped. The blood looks milkv. The red cells are 

 reduced to 700,000 per c.mm., some are nucleated. There are also 

 polychromatic and mast cells. 



Red Cells. 



Variation in colour usually indicates the amount of hb. A rough 

 indication of anasmia is thus given, 



Poikiloc^^tosis as seen in pernicious auccmia ma}' be imitated 

 artificially in making the film by drawing the cells down one slide 

 with another, but the elongation is in the same direction in all the 

 cells. To avoid it in making a blood film \\\\h two slides, the drop 

 of blood should be drawn away from the operator and not pushed awav 

 with the second slide. 



Nucleated red cells may appear in normal blood, ]3rimar\- and 

 secondary ana?mia. The nucleus may be divided, or it may appear 

 as two rounded bodies. 



Polychromatic cells are not uncommon in the ana?mias, especiallv 

 in malaria. They are degenerated red cells and take up both eosin 

 and methylene blue. 



Some red cells are basophilic; thev show slippled dots peripherally 

 which may be polychromatic. Thev indicate a degenerative process. 

 They are very common in lead poisoning. They do not indicate 

 latent malaria as Plehn supposed. 



COUNTING BLOOD CELLS AND ESTIMATING HB. 

 To Count Red Cells. 



Use Gowers's hfemacytometer. 



Draw into the pipette blood from a small needle wound in the lobe 

 of the ear or finger-lip up lo the mark on the stem near the bulb. 



Fill to mark above the bulb with Hayem's solution. 



Shake well, then place one drop on special slide provided. 



Place on this a cover slip. The drop should cover the central disc, 

 but should not run over this so as to come between the cover slip and 



