ANTI-BNZYME IMMUNITY 



355 



Moreover, the degree of neutralization of the inhibition was pro- 

 portional to the ct-antitoxin concentration; an antitoxin concentra- 

 tion of 4X10~^ produced 88 per cent neutralization. Other antisera, 

 such as septique, oedematiens, tetanus, and normal serum produced 

 no appreciable inactivation of the toxin. 



c. Pharmacological Activity of the Toxins of CI. Welchii. Biolog- 

 ical changes resulting from the action of toxins has been the subject of 

 a series of studies by Kellaway, Trethewie, and Turner (1940a, 1940b) 

 and Kellaway and Trethewie (1941). The following discussion is 

 based on their findings. 



In the first two studies, they investigated the effects of the toxin 

 of CI. welchii of type D. The culture filtrate was treated with am- 

 monium sulfate to obtain 65 per cent saturation. The precipitated 

 toxin was then treated with 50 per cent alcohol in the cold to remove 

 the histamine-like impurities, and further purifications were affected 

 in the cold. The M.L.D. of the final product for a 20 g. mouse was 

 8 micrograms, or 8X10~^ g. The symptoms fairly regularly observed 

 by intravenous injections in young lambs were similar to the clinical 

 manifestations of poisoning and particularly to the convulsions which 

 occur in the natural disease in which the toxin is absorbed from the 

 alimentary tract. Intravenous injection in lambs caused convulsions 

 by direct action of the toxin on the central nervous system— probably 

 mainly upon the basal ganglia. It was stated that death occurring as 

 a result of injections might be due to failure of respiration, or to cardiac 

 failure. Hemorrhages in the heart in lambs and hemorrhagic edema 

 of the lungs in lambs, rabbits and cats after intravenous injection of 

 toxin were frequent occurrences. Antitoxin neutralized these effects 

 of the toxin. 



The authors interpreted the occurrence of hemorrhagic effects of 



