THE PNEUMOCOCCIDAL POWER OF WHOLE BLOOD

Abstract

I. A method is described for measuring the capacity of 0.5 cc. of uncoagulated human blood to kill pneumo-cocci. Blood of 17 of 27 hospital patients who had not had lobar pneumonia, killed 100-10,000 virulent, Type I pneumococci; blood of 9 of the same group killed none. When both mouse protection and whole-blood-pneumo-coccidalpower were measured, 6 subjects had both; 10 had whole-blood-pneumococcidal power alone; and 3 had neither. II. Blood of 7 patients acutely ill from Type I lobar pneumonia, killed 0-10,000 pneumococci in 6 observations made on the 1st, 2nd, 3rd, 4th and 5th days before crisis. Four blood samples taken on the 1st, 2nd, and 3rd days before crisis killed 100,000-1,000,000; 13 samples examined during the 1st wk. after crisis, killed 100,000-1,000,000; 13 samples examined during the 2nd, 3rd and 4th wks. after crisis, killed 1000-100,000. Before crisis, bacteremia was found associated with great variations in pneumococcidal power of the blood, 0-1,000,000 pneumococci being killed. Bacteremia or sepsis about the time of death were usually associated with no pneumococcidal power, but in 1 of 3 cases moderate pneumococcidal and self-sterilizing powers were present. In the absence of pneumococcus complications, the patients'' blood often contained pneumococci and was at the same time markedly pneumococcidal. Administration of concentrated antipneumococcus serum to patients with lobar pneumonia produced sudden rise in pneumococcidal power of blood to that level found in patients having successfully passed crisis.