28 



LOCAL TISSUE REACTIVITY 



Table i 



TITRATION OF REACHINCi FAC;TOR.S AGAINST CONSTANT 

 SKINT^REPARATORY DOSES 



Fil- 

 trate 



A36 



989 

 852 



971 

 1078 



A3 4 

 A38 

 1139 



A32 

 Aio 



Strain used Jar preparation 

 of filtrate 



Ty Tl stock 



Ty Tl 245 ser 



Ty 157 stock 



Ty 159 



44D ser.23 (group i) . . 

 44D mouscie (group i) 



44B (group III) 



44D ser. 33 (group i) . . , 



44D (group i) 



44D (group i) 



Highest 

 dilution 



oj filtrate 

 eliciting 



reactions 



600 



200 



1000 



1 100 



1200 



1000 



800 



1000 



300 



500 



Per cent 

 positive 

 rabbits 



with 

 highest 

 dilution 

 eliciting 

 reactions 



50 

 50 

 25 

 50 

 25 

 50 

 75 

 50 

 25 

 25 



Lowest 

 dilution 

 of filtrate 

 showing 



800 



400 



1200 



1400 



1400 



1200 



1000 



1200 



400 



700 



No. of 



reacting 



2inits per 



c.c. of 



filtrate 



700 



300 



1 100 



1250 



1300 



I 100 



900 



1 100 



350 



600 



Per cent of posi- 

 tive rabbits with 

 various numbers 

 oJ reacting units 



It may be concluded that the titrations of the reacting factors 

 against a constant skin-preparatory dose (single site prepared) to 

 the end-point afford the method of choice. Dikited materials in- 

 jected intravenously prodtice no lethal effect. Moreover, inasmuch 

 as in all netitralization experiments, to be subsecpiently described, 

 large amounts of the reacting factors are titrated against a con- 

 stant amoimt of serum, the natinal variations in stisceptibility 

 of animals is completely overcome and, therefore, acciuate deter- 

 minations of the neiUralizing potency are made possible throtigh 

 the tise of this method. 



RECAPITULATION 



Microorganisms in which hitherto no true exotoxins have been 

 demonstrated were selected for the \vork about to be described 

 in this monograj)h. It \vas assumed that those microorganisms 

 may produce injuries in animal tissue through a mechanism alto- 

 gether different from the direct injurious effect exerted by diph- 

 theria, botidinus, tetanus and other exotoxins. With this assump- 

 tion in mind, the following basic experiments were carried out. 



Rabbits received a single intradermal injection of B. typhosus 

 culture filtrate followed twenty-foiu' hours later by an intravenous 



