IS 



and the colonies that developed on each were counted with the results 

 shown in Table 8. 



The table shows that both strains of streptococcus used multiplied 

 in the cell- free serum; that the defibrinated blood destroyed many of 

 the non-virulent and some of the virulent cocci, and the "suspension of 

 leucocytes" destroyed more cocci of either strain than the defibrinated 

 blood. The only difference between the defibrinated blood and the "sus- 

 pension of the leucocytes" lay in the fact that the latter contained nearly 

 twice as many leucocytes as the former. 



The fact that the streptococcidal power of the blood is dependent 

 on the number of leucocytes it contains per cubic millimeter has also 

 been demonstrated by a second experiment. 



Experiment 2. Shortly after a patient's admission into the hospital, 

 3 c. c. of blood was drawn from a vein at the elbow and defibrinated. 

 The leucocyte count at this time was 11,000. The blood was divided 

 equally among three tubes, and each tube was inoculated with strepto- 

 coccus culture and two loopfuls from each were plated at intervals. 

 Shortly after drawing the blood, the patient was injected under the skin 

 of the back with TO c. c. of an antistreptococcus serum. This brought 

 about an increase in the leucocytes up to 15,000, five hours after the in- 

 jection. Three c. c. of blood was again drawn from the vein at the elbow 

 and its effect on streptococci tested as before. The results of the experi- 

 ments are shown in Table 9. 



TABLE 9. 



Colonies on Agar Plates, 



Strepto- Leucocyte 



cocci. count. Immecl. 2 to 3 hrs. 5 hrs. 



800 Blood before injection 11000 1100 360 200 



B104 Blood before injection 390 380 4000 



381 Blood before injection , 100 500 Many 



300 Blood 5 hours after injection 15000 1300 44 



B104 Blood 5 hours after injection 412 240 600 



381 Blood 5 hours after injection 150 270 3000 



The blood drawn after the injection of the serum, when the leucocy- 

 tosis was high, has a greater streptococcidal power than that drawn before 

 the injection. It would not be safe to conclude that this difference in the 

 streptococcidal power is due entirely to the difference of the leucocyte 

 count. Some of it may be due to an antitoxic or opsonic action of the 

 serum or to a stimulation of the leucocytes. This supposition loses most 

 of its force when we consider the fact that the addition of from I to 5 

 per cent of this antistreptococcus serum to defibrinated blood in vitro 



