LEUCOCYTES. WHITE BLOOD GLOBULES. 



The Leucocytes vary widely in health and much more in dis- 

 ease. The average ratio to the red cells may be set down as 

 1 : 357 in man, but in the domestic animals Nocard found them 

 i:8oo to i:iioo. The variation in different parts of the vas- 

 cular system and at different times of the day is striking and 

 suggestive. In the splenic vein i : 60 ; in the hepatic vein i : 170 ; 

 in the morning fasting i : 716 ; half an hour after breakfast i : 347 j 

 in boys i : 226 ; in girls i : 397 ; in men i : 346 ; in old men i : 381 ; 

 in menstruating women 1:247; ^^ pregnant women 1:287 

 (Strieker). 



They may number from 5000 to 15000 per c.mm. They are 

 larger than the red cells, spherical (amoeboid), colorless, reticu- 

 lated and with one or more refractive nuclei. They show not 

 only amoeboid movements, but also what are considered as 

 Brownian movements, the latter some time after having been 

 drawn and perhaps indicating the approaching death of the cell. 

 Their numbers diminish materially in shed blood. They show 

 nodes at the crossing of the fibres of the reticulum and granules. 



Varieties of leucocytes. By staining, the leucocytes can be 

 differentiated into at least five different kinds : 



a. Lymphocytes. 4.6 to ii/n. Horse. 



b. Large mononuclear leucocytes. 



c. Polynuclear neutrophile leucocytes. 



d. Eosinophile leucocytes. 



e. Mast-cells. Basophile. 



1st. Lymphocytes of variable size, but approximating to the 

 cells of lymph, are generally larger than red cells (5 to ii/x) and 

 when stained in slightly neutralized methylin blue show small 

 violet-shaped granules. In the horse these make 24 to 35 per 

 cent, of the leucocytes. 



2d. Large mononuclear leucocytes, of variable size, from the 

 lymphocyte up, but embracing the largest of the white corpus- 

 cles, stain faintly red in Ehrlich's triacid solution of fuchsine 

 and methyle green, with nucleus circular, horseshoe-shaped or 

 elongated. In the horse these form from 3 to 4 per cent, of the 

 leucocytes. 



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