72 LOCAL ILSSUE REACIIVLIY 



tiiil)i(l. riu' filtrate ol the (iiltinc in ilic .s;u {ontaiiicd the active 

 j)riiuij)les, wliilst the filtrate of the broth outside of the sac was 

 iliac ti\e. 



Plant (i<)'52) studied the ])iien()inenon-i)i()diicinj^ jjoteiicy of 

 Beikefeld "V^" filtrates and sii})ernatant fluid ( iiltures ol Spiro- 

 clieta jjallidd R-,'^() (Reiter) in media ol Plant and Kassowitz with 

 entirely negative results. The materials were then precipitated 

 by liim Avith ammonium sulphate and dialyzed against rinniing 

 water for forty-eight honrs. Ral)bits were pre])ared by intrader- 

 mal injection of 0.2 c.c. of the dialyzed filtrate and t\venty-four 

 hours later, injected intravenously with five and ten times the 

 dose of the same filtrate. Positive reactions were obtained in ral)- 

 fjits thtis treated; althotigh the original filtrate (without ammo- 

 nitim stilphate precipitation) employed in equivalent doses gave 

 no reactions. In finther experiments Plant found that the dialysis 

 alone (without preliminary precipitation with ammonium sul- 

 phate) transformed inactive filtrates into active ones. It was sup- 

 ]30sed by him that inhibitory substances are present in the filtrates 

 which may be eliminated by dialysis. These inhibitory substances 

 could be also precipitated by alcohol and successfully removed by 

 dialysis of the precipitate against running w^ater. According to 

 Plant, it is important to select a suitable membrane (Schleicher 

 and Schiill (N579) (Diffusionshiilse) . The selection of the strain 

 of spirochete also proved of importance. Whilst strains Ra,; and 

 Kross K22 were active, rabbit testicular syphilomas inoculated Avith 

 Trufli and Nichols strains and water spirochete (Spiroclieta pseu- 

 doicteroides) gave negative results. 



It is interesting that in this author's experiments the most ac- 

 tive principles ^vere obtained from twenty-four to forty-eight hour 

 old cultures (33 rabbits, 100 per cent) . Six to eight day old cul- 

 tures gave only 75 per cent of positive results ^vhilst fotu' week 

 old cultures were completely inactive. 



Recently, quantitative studies on the dialysis of B. typhosus, 

 meningococcus and B. coli culture filtrates were undertaken 

 (Shwartzman, Morell, and Sobotka, 1937) . A simple and easily 

 reproducible method of dialysis developed by Morell allo\\ed the 

 carrying out of the procedure under strictly sterile conditions for 

 as long as one week. 



When an active filtrate was titrated to the end-point, the titer 

 computed was the mean of the dilutions at ^vhich positive and 



