TIJE EXAMINATION OF THE HLOOD 605 



TO FIX BLOOD FILMS. 



Agents. — Time, lieat, Ilg- perchloride, formalin, csmic acid, 

 absolute alcohol. 



The best is absolute alcohol and ether, equal parts. 



Place blood films in it from ten minutes to ad lib. 



This solution does not lose its fixative power. 



Blood films to be stained with Leishman's need no fixing at all. 



A NORMAL DIFFERENTIAL BLOOD COUNT WILL SHOW :— 



Some '' blood dust " which must not be taken for parasites, though 

 Brownian movement may be present. 



Leucocytes. — 6,000-8,000 per c.mm. 



Lymphocytes. — 15-25 per cent. They have a large deep staining 

 nucleus with little protoplasm. 



Large Mononuclears. — 5-10 per cent. These are larger cells with 

 a larger and paler nucleus with more protoplasm. 



Polymorphonuclears. — 65-75 P^*' cent. There are several nuclei 

 which are connected by nuclear filaments. 



Eosinophiles. — 1-3 per cent. The granules show an affinity for 

 acid stains. 



Transitional. — Few. These have a horseshoe-shaped nucleus. 



Remember that: — 



(i) The lymphocytes are increased during digestion, scurvy (60 per 

 cent, are Ivmphocvtes), lymphatic leukaemia (70-85 per cent, are 

 lymphocytes), enteric and Malta fever, but these latter are not constant. 



(2) The large mononuclears are increased during malarial fever 

 (15-20 per cent.). This is not reduced after taking quinine. Quinine 

 may have cleared up the parasites, but the above condition will assist 

 the diagnosis. 



(3) The polymorphonuclears are increased physiologically during 

 youth and pregnancv, and pathologically during suppuration and 

 pneumonia. 



(4) Eosinophiles are increased during worm infections, e.g., 

 trichiasis, bilharziasis, filariasis, &c. Trypanosomiasis, verminous 

 conditions, asthma and bronchitis, urticaria, pemphigus, and after 

 dietetic errors, such as " high " cheese, venison, &c. 



(5) The total leucoc\'tes are diminished in trypanosomiasis and 

 knia-azar (,^,000 or less). 



ABNORMAL BLOOD CELLS. 



White Cells. 



Mast cells are degenerated leucocytes of the polynuclear type. 



The nucleus stains poorly. The granules are coarse and are called 

 meta-chromatic granules, because they neither take h^ematoxylin nor 

 eosin well, but stain better with a combination of the two. 



