VACCINE-THERAPY 



13 



driven centrifuge is a thing much to be desired, and which 

 is in most common use. 



Centrifugalizing Blood. — The quantity of blood required 

 is placed in a blood-tube, and before coagulation takes 

 place is mixed with citrate solution and centrifugalized. 

 The red cells are thrown down first by reason of their 

 specific gravity, appearing at the bottom as a red layer ; 



^wmmM> ,y ' 



Fig. 7. — Water-drivex Centrifuge. 



next the white corpuscles as a grey layer ; and on the top 

 will be found the liquor sanguinis comparatively clear. 

 To complete this process one has to use the centrifugal 

 force from ten to fifteen minutes. 



Centrifugalizing Urine. — To centrif ugalize urine, specially 

 graduated tubes, tapering to one end, are used, the speed 

 required being about 2,500 revolutions per minute. 



Where one is searching for bacteria in limited numbers, 



