24 LOCAL ILSSUE REACTIVITY 



Method I : Reciprocal titrations of various skin-preparatory 

 doses against various reacting doses : 



In these titrations several sites oi the skin Avere prej^ared simul- 

 taneously with various dilutions ol tlie material tested and twenty- 

 loin- hoin\s later, rabbits thus prepared were divided into groups 

 of 4-6, and injected intravenously. Each group of rabbits received 

 intravenously a different dilution of the same material (Shwartz- 

 man, 1929/;, e) . 



Meningococcus "agar washings" culture filtrates Avere used: 



Protocol 10: Thirty-six ral)bits recci\cd each five simultaneous intra- 

 dermal iujec tions ot 0.25 t.c. ol inuliluted filtrate and of the filtrate diluted 

 with o.g per cent NaCl solution 1:10, i.-^o, 1:10. and 1:80. Twenty-four hours 

 after the intradermal injections, these i\6 rabbits were divided into 6 equal 

 groups. Each group received a single intravenous injection ot the filtrate. 

 The first group received 2.5 c.c. per kilo of body weight. The second group 

 received 1.5 c.c, the third group 1.0 c.c, the fourth group 0.5 c.c, the fifth 

 group 0.25 c.c, and the sixth group 0.1 c.c, respectively, per kilo of body 

 weight. The intravenous injection proved very toxic. Ten rabbits of the first 

 2 groups (2.5 c.c, and 1.5 c.c), and 2 rabbits ot each of the following 4 

 groups died within one to five hours following the intravenous injection. The 

 skin reactions of the surviving 18 rabbits were read five hours after the intra- 

 venous injections. All of these rabbits showed severe hemorrhagic necrosis 

 varying from 3x2 cm. to 3 x 4 cm. in size in areas previously prepared with 

 luidiluted filtrate. Only one rabbit in each of the six groups showed hemor- 

 rhagic necrosis in areas prepared with the dilution 1:10. All the areas pre- 

 pared with higher dilutions remained negative. 



Protocol II : Twenty-four rabbits received each six simultaneous intra- 

 dermal injections of 0.25 c.c of undiluted filtrate, and of the filtrate diluted 

 with 0.9 per cent NaCl solution 1:2. 1:4, 1:6. 1:8, and 1:10. Twenty-four hovus 

 after the intradermal injections, the rabbits were divided into 4 groups of 

 6 each; each group received a single intravenous injection of the filtrate. 

 The first group received 0.4 c.c. per kilo of body weight. The second group 

 received 0.3 c.c, the third group 0.2 c.c, and the fourth group 0.1 c.c, re- 

 spectively, per kilo of body weight. Three rabbits of the first group, one 

 rabbit of the second, and one rabbit of the third died within one to five 

 hours following the intravenous injection. All of the remaining iq rabbits 

 showed severe hemorrhagic necrosis in areas previously prepared ^vith mi- 

 diluted and diluted 1:2 filtrate. There were fluctuations in the skin-prepara- 

 tory eftect of higher dilutions. Nevertheless, reactions were obtained even in 

 sites prepared with dilution 1:10, provided the intravenous dose was not 

 less than 0.3 c.c per kilo of body weight. This is corroborated by the experi- 

 ment recorded in the following protocol. 



Protocol 12: Fourteen rabbits received each six simultaneous intra- 

 dermal injections of the diluted filtrate. The upper and lower right and 

 left areas of the abdominal wall were injected with the dilution 1:2, and 

 the middle right and left areas with the dilution 1:3 of the filtrate. Twenty- 



