PHYSICO-CHEMICAL PROPERTIES 75 



FORMALIN DETOXIFICATION OF ACTIVE PRINCIPLES 



Burnet (1931) ^vas the first one to report on the effect of for- 

 malin on the active principles of the phenomenon of local skin 

 reactivity. 



A Besredka preparation of B. dyseyiteriae Flexner was treated 

 with 0.2 per cent of formalin and the ttibe left sealed at 37° c. 

 for one month. The skin ol rabbits ^vas prepared ^vith the un- 

 treated preparation and the toxoid, and twenty-four hours later 

 the rabbits received an intravenous injection either of 0.5 c.c. of 

 untreated preparation or toxoid. The toxoid as a skin-preparatory 

 agent provoked either no reaction or a reaction below the region 

 injected. Toxoid used intravenotisly ^vas as effective as an unal- 

 tered preparation. According to Burnet, a single intradermal 

 injection of toxoid followed by a suitable intraxenous injection 

 of the active principles gave rather varial^le results depending on 

 the reactivity of the rabbit. A common form of the reaction xvas a 

 ring of ptirpura around the central pale area. With very reactive 

 rabbits there was more extensive purpura with only a small sharply 

 outlined pale center, but in most the reactions were a small cres- 

 cent below the infiltrated area or nothing at all. 



As pointed out, the reacting potency of a preparation may be 

 considerably higher than its skin-preparatory potency. The inter- 

 pretation of Burnet's exj)eriments l)ecomes easy if it is granted 

 tiiat his treatment with h)rmalin elicited only a partial inactixa- 

 tion of the preparation, Avitii a proportionately more considerable 

 reduction in preparatory potency than in reacting potency. Reac- 

 tions oi similar appearance \vere observed by me with xveak fil 

 trates and liltrates partially inactivated by expostire to heat. 



Klein (1932) , in my laboratories, "was able to inactivate menin- 

 gococcus "agar xvashings" filtrates l)y prolonged exposure tc^ 

 formalin. Inasmuch as he carried out extensi\e studies on the 

 antigenicity of the formalinized preparations, it seems more ap- 

 {^ropriate to discuss his results in Chapter iv. 



USE OF METHODS OF ECKER AND RIMINGTON FOR CC^NCENTRATION 

 AND PURIFICATION OF THE ACTIVE PRINCIPLES 



Ecker and Rimington (1917, 1927) showed that synthetic 

 medium cultine filtrates of the Aerytrycke type of B. jjara- 

 lyjjhosus. concentrated /// iinciio and dialyzed, ):)roduccd a raj)id 



