INTRODUCTION 11 



1:40, and 1:80. The filtrate was of a somewhat lower potency than those 

 described later, shice from 15 to 20 c.c. was used for washing each Kolle 

 flask instead of the customary 3 to 4 c.c. The readings of the primary effect 

 of these injections were made twenty-three to twenty-four hours later. The 

 undiluted filtrate produced moderate erythema (2-j-) in three rabbits, slight 

 reddening (i-[-) i'^ ^ rabbits, and doubtful reddening, or no erythema in 

 the remaining 25 rabbits. With the dilution 1:10, 2 rabbits showed a moder- 

 ate erythema (2-f-) , and the remaining rabbits very slight erythema or no 

 reactions whatsoever. The dilutions 1:20 and 1:40 produced 2-|- erythema 

 in 3 rabbits. None of the remaining injected areas showed any visible primary 

 effect of the filtrate. 



In a stdjsequent experiment, 24 rabbits received each six simultaneous in- 

 tradermal injections of 0.25 c.c. of the above undiluted filtrate and of the 

 filtrate diluted with 0.9 per cent NaCl solution 1:2, 1:4, 1:6, and 1:10. The 

 primary effect of these injections, as read twenty-four hours later, was in- 

 significant. Only 3 rabbits showed moderate erythema and the remaining 

 rabbits had either "i-|-" reddening or no erythema whatsoever. Occasionally, 

 there were swellings. 



The primary effect of a single injection of meningococcus 

 "agar washings" filtrates of concentration higher than in the fil- 

 trates studied above (i.e., each Kolle flask cultine washed Avith 3 

 to 4 c.c. of saline containing 0.4 per cent phenol) , was as follows, 

 in experiments on 1002 rabbits. 



Forty-tAvo and four-tenths per cent of rabbits showed no pri- 

 mary reactions in the gross, t^venty-four hoius after the injection; 

 39.2 per cent gave doubtful primary reactions; whilst in 7.7 per 

 cent erythemas were elicited which could be classified as 4-]-; 

 the rjemaining rabbits sho\ved erythemas of an intensity varying 

 from i-|- to 3-|-; 17.3 per cent showed distinct swellings at the 

 prepared sites Avith and without erythema. Here again, the swell- 

 ings appeared to bear no relationship to the erythematous pri- 

 mary reactions. About 2.5 per cent of the rabbits showed strong 

 primary hemorrhagic reactions and about 1.7 per cent shoAved 

 pimctiform hemorrhagic reacticjns. Thus, in 4.2 per cent there 

 appeared reactions -which could be confused Avith the reaction of 

 the phenomenon of local skin reactivity to bacterial filtrates. 

 These reactions were obtained Avith but a iew preparations and 

 did not appear if th^^in was injected Avith a dilution of 1:2 

 or 1:3 thereof. J^ 



As may be seen, tWe above described primary reactions obtained 

 with bacterial filtrates employed in this work are sharply con- 

 trasted by the hemorrhagic reaction folloAving the intravenous in- 

 jection of potent filtrates. It may be important to emphasize again 



