VARIETIES OF LEUCOCYTES. 421 



acute bacterial infections of various kinds (11). The cell 

 has a precise and limited distribution in the body, for under 

 normal circumstances it occurs only in the blood, there 

 constituting usually about 75 per cent, of all the leucocytes. 

 It is certain that it has been detected multiplying by 

 karyomitosis while still within the circulation and under 

 normal conditions ; it may therefore pass its whole exist- 

 ence within the blood-vessels ; yet specimens of it showing 

 karyomitosis are very uncommon (12). Some hold that it 

 undergoes direct division more frequently (13). It is 

 essentially a blood-cell, and is present in fcetal blood before 

 the lymphocyte appears (14). 



IV. The Coarsely Granular Oxyphil Cell. 



This cell is large, usually above 12 ^ diameter. Its 

 nucleus is of less irregular shape than that of the finely 

 granular oxyphil cell ; very often its nucleus is reniform, or 

 in the form of a horseshoe. The oranules contained in 

 the cell-body are large, shining and highly refractive. In 

 shape they vary in different animal species ; most often 

 they are spherical, but in the cat are ovoids, and in the 

 horse cuboids (10). They are largest and least numerous 

 in the cells of the horse, amounting generally to not more 

 than a dozen, whereas in many animals one cell may contain 

 a hundred of them. They are remarkably readily and 

 deeply stained by "acid" dyes, perhaps most readily in 

 human blood, and least readily in rat's blood. When to 

 fresh undried rabbit's blood a little Ehrlich-Biondi fluid is 

 added the granules in the still living cell take up the acid 

 fuchsin of the mixture. Treated with osmic peroxide the 

 granules turn brown almost as deeply as do fat particles, 

 but they are not soluble in alcohol or ether. In their high 

 refraction and oxyphil affinity they resemble the red blood cor- 

 puscles, and like them contain both phosphorus (10) and iron 

 (15); but they are quite colourless. Some observers from their 

 microchemical reactions have concluded that the granules 

 are proteid (16) ; if so the proteid may be nucleo-albumin ; 

 but these cells do not appear to play a part in the clotting 

 of the blood or lymph. The granules may be considered 



