16 



In the preparation of his serum. Kyes obtained cultures from 

 the blood or lungs of patients with acute lobar pneumonia. They 

 grown for -IS hours on blood-agar, slanted in flasks which 

 gave a surface equal to 2<> ordinary test-tube slants, and were 

 inoculated (alive) intraperitoneally. The initial dose was 

 usually equal to about 240 test-tube slants, and the average 

 subsequent doses equalled about 400 slants. Injections were 

 made every other week and the total period of inoculation varied 

 from four months to 2 years. Serum was obtained by bleeding 

 the fowls once a fortnight, the week of bleeding alternating with 

 that of injection. " In a few groups bleedings were commenced 

 " following the 6th injection, but the bulk of the serum employed 

 " in the clinical tests was taken from the fowls having received 

 " not fewer than eight nor more than thirty inoculations. The 

 " blood was drawn by incising the leg vein and from 20 to 40 c.c. 

 * : obtained from each fowl at a bleeding. The blood corpuscles 

 " were removed by centrifugalisation and the serum, diluted one- 

 " half with -85 per cent. NaCl, was filtered through Berkefeld 

 " candles." Kyes found that the sera possessed a high content 

 of specific antibodies, but he did not regard content of agglutinins 

 as an index of the therapeutic value of a serum. A univalent high 

 tit re serum (1 : 100,000) was tested against 77 strains of all 

 sorts and agglutinated them all (nine only up to 1 : 20, but the 

 majority up to 1 : 500). He thought it open to question whether 

 weak sera really established fundamental differences between 

 different strains. " On the other hand, it is of course well 

 " established, and quite apart from any particular classification, 

 " that various strains of pneumococci do display distinct differences 

 " at a given time and also that a given strain displays quite as 

 ' distinct differences at various times. In producing each lot 

 M of serum, therefore, I have inoculated a great variety of strains, 

 " including four of Pneumococcus 7nucosus." 



Recent French Investigations. 



A brief account must now be given of French work on the 

 serological classification of pneumococci and the production 

 of immune sera. 



In 1918, Nicolle, Jouan, and Debains* expressed the view- 

 that the classification of pneumococci was greatly simplified 

 by adopting the method of Porges, who had found that capsulated 

 bacilli could be made agglutinable by treatment with dilute 

 acid and subsequent neutralisation. After applying this treat- 

 ment, they found that all pneumococci became agglutinable by 

 the serum appropriate to their race, and that the American 

 scrap-heap (" Type IV ") disappeared; Their technique was as 

 follows. The centrifugalised deposit of a liquid culture was 

 suspended ID saline (1 centigramme to 20 c.c). To this was 

 added o- 1 c.c. of normal HC1 ; sometimes more acid was necessary 

 (from 0-2 to 0-5 c.c). Then the tub e was immersed for five 

 * C. R. Soc. Biol., Vol. 81, p. S3U. 



