694 OPSONISATION FKOM A BACTERIAL POINT OF VIEW, ETC., 



In the following, the opportunity was taken to test the action 

 of bacteria which had been grown in ordinary neutral bouillon 

 and in the same with the addition of 2% of saccharose. 



Washed bacteria from 



Cocci per leucocyte. 



ordinary mixing(4 times) 



Neutral bouillon 



2% saccharose bouillon. 



5-2-5-S-4-9 

 3-7-4-0 



excessive mixing(20 times) 



88-60-6-0 

 4-8-5-6 



The differences between the duplicates of the excessive mixing 

 are considerable, and upon consideration it appeared possible 

 that they arose from variations in the bore of the capillary 

 pipettes and especially in the internal diameter of the orifice. 

 In the next experiment, an idea of the average bore was obtained 

 by sucking a volume of water into the pipettes and measuring 

 the lengths of tube which the volume occupied. The pipettes 

 were in pairs, having been made from one piece of tubing. The 

 lengths of the volume of water are in centimeters and in the 

 table are enclosed in brackets. 





Cocci per leucocyte. 





ordinary 



mixing 



(4 times). 



excessive 



mixing 



(20 times). 



difference for 



16 times 



of mixing. 



Pipette with wide bore ( = 3 "0cm.) 

 Pipette with wide bore ( = 4'()cm.) 

 Pipette with narrow bore( =5 -6cm.) 

 Pipette with narrow bore( = 6 '6cm. ) 



3 2 

 31 

 3-3 

 3 2 



3 6 



3-7 

 4-1 

 45 



0-4 

 0-6 

 0-8 

 1-3 



In the case of the narrowest pipette, the phagocytic index or 

 number of cocci ingested per leucocyte has been raised nearly 0T 

 for every time of mixing. It is evident that in mixing the sus- 

 pensions the fluid should be blown in and out of the pipette a 

 definite number of times. 



On the whole this portion of the research did not hold out any 

 hope of shortening the process of determining the opsonic activity 

 of serum. It is absolutely necessary, as Sir A. E Wright told 

 me, to count 100 leucocytes, as smaller counts are liable to give 



