682 OPSONISATION FROM A BACTERIAL POINT OF VIEW, ETC., 



sediment which contained half the corpuscles was transferred to a 



small tube, mixed with more saline and turned until the cells 



were completely deposited. 



Oomuscular I u PP er P or ti° n (20vols.) many leucocytes,chiefly mononuclears. 



sediment in J middle portion (lOvols.) no leucocytes. 



0-85°/ saline! ^ ower P or *i° n (20vols.) very many leucocytes, chiefly poly- 



/o v morphs. 



Corpuscular sediment f upper half, no leucocytes. 



in 0*6 % saline. (lower half, many mono- and polynuclears. 



It is clear from these experiments that by slowly centrifugalis- 

 ing the corpuscles, one can finally obtain a suspension or 

 " separate" very rich in the mobile phagocytes. 



By quickly centrifugalising, and especially with the corpuscles 

 in a small hematocrit tube, the conditions are reversed and the 

 bulk of the leucocytes are found in the upper layers, probably on 

 account of the increased speed causing the red cells to travel 

 edge on and therefore faster than the leucocytes. Furthermore, 

 in the small tubes the red corpuscles have not so far to travel 

 and friction does not influence the deposition to so great an 

 extent. 



The concentration of the polymo?'phonuclear$. — A concentration 

 of the white corpuscles can also be obtained by slowly smearing 

 the thick suspension over glass and pipetting up the portion 

 which has followed the smearing implement. The principle is 

 the same as making the smears on the glass slides. Unfortu- 

 nately a number of polymorphs are lost at the margins of this 

 large smear. It is possible that the facility with which the 

 leucocytes travel with the stream accounts for so many being 

 found in the "cream," as obtained by sloping the tube and 

 allowing the upper layers of the sediment to run away from the 

 lower. 



The same thing obtains when preparing the smears. T'ie 

 greater part of the white corpuscles of the mixed drop run into 

 the capillary pipette before the bulk of the red corpuscles, so that 

 in blowing out the mixture the first droplet is relatively poor in 

 leucocytes and the last droplet correspondingly rich. Further- 

 more, the more mobile leucocytes with the greater number of 

 ingested bacteria are in the droplet last to be blown out. 



