PASSIVE IMMUNIZATION 467 



subject of extensive studies by Wadsworth, 70 Hiss, 77 and many others. 

 For the sake of obtaining plentiful growth for agglutination purposes, 

 Hiss has recommended cultivation in 1 per cent glucose broth with the 

 addition of small amounts of sterile calcium carbonate to absorb acid 

 formed from the glucose. Pneumococci do not regularly agglutinate 

 in diluted immune sera and agglutinations are best studied in sus- 

 pensions of more concentrated immune serum. Agglutination begins 

 at the end of about 15 minutes, and can be studied both by formation 

 of clumps and by the sediment. See preceding paragraphs on typing. 

 Specific precipitating antibodies have been demonstrated in pneu- 

 mococcus immune serum by Neufeld, 78 Wadsworth, 79 Hiss, 80 and 

 others, the organism for such tests being brought into solution either 

 with bile or with concentrated salt solution. Such sera also contain 

 powerful opsonic substances, or, as Neufeld and Rimpau 81 prefer to 

 call them, "bacteriotropins. " It seems most likely that such phago- 

 cytosis-aiding substances are most powerfully concerned in protection 

 and cure. Clough 82 has reported an increased of opsonins at the time 

 and crisis, and Dochez 83 has shown that protective substances may 

 appear in the serum at or soon after the time of crisis. The outcome 

 of a case according to Cole depends very largely on the virulence of 

 the organism and on the ability of the body first to limit the local 

 infection and to prevent the invasion of the blood with the organisms. 

 In this process, of course, the protective and opsonic bacteriotropic 

 substances would play a most important part. 



PASSIVE IMMUNIZATION AND USE OF PROTECTIVE SERA 



The history of attempts to produce sera for passive immunization 

 in man is extensive. Washburn, 84 Mennes, 85 Pane 86 and many others 

 in the past have succeeded in protecting animals with such sera, but 



76 Wadsworth, loc cit. 



n Hiss, Jour. Exp. Med., vii, 1905. 



78 Neufeld, Zeit. f . Hyg., 1902, xi. 



79 Wadsworth, loc. cit. 



80 Hiss, Jour. Exp. Med., vii, 1905. 



81 Neufeld and Eimpau, Deut. med. Woch., 1904. 



82 Clough, Johns Hopkins Hosp. Bull., Oct., 1913. 



83 Dochez, Jour. Exp. Med., 1913. 



84 Washburn, Brit. Med. Jour., 1897. 



85 Mennes, Zeit. f . Hyg., 1897. 

 M Pane, Eif. med., 1897. 



