358 IMMUNO-CATALYSIS 



of the disappearance of antitoxin, MacLennan and MacFarlane (1945) 

 concluded that the circulating antitoxin is incapable of arresting the 

 local spread of gas-gangrene, and that circulating antitoxin will not 

 prevent death, apparently from toxemia, as a result of this local 

 infection. The presence of an excess of antitoxin in the blood-stream 

 and wound area will not of itself prevent a fatal outcome. It was 

 assumed that, if death is directly due to toxin and cannot be averted by 

 antitoxin, vital tissues have been irreparably damaged by toxin before 

 antitoxin is given, or that the antitoxin cannot protect them from 

 circulating toxin.* MacFarlane and MacLennan (1945) are, never- 

 theless, of the opinion that, while the primary lethal factor is not 

 neutralized by antitoxin and can only be eliminated by surgery, there 

 also is some absorption of bacterial toxin amenable to antitoxin treat- 

 ment. In connection with the questions of toxin-antitoxin reaction in 

 gas-gangrene, the observations of Zamecnik and Lipmann (1947) 

 seem to be of considerable significance. They found that toxin-anti- 

 toxin combination is strongly inhibited if toxin and the specific sub- 

 strate lecithin come together before antitoxin has a chance to react with 

 the toxin. Even with a 20-fold excess amount of antitoxin the enzymic 

 activity of toxin was marked. These facts would appear to indicate that 

 in gas-gangrene, the toxin excreted by the infective agent will react 

 with the substrate present in the tissue. Subsequent administration 

 of antitoxin will be incapable to prevent the enzyme reaction from con- 

 tinuing. 



In gas-gangrene toxemia, MacFarlane and MacLennan (1945) 

 could not find lecithinase in the circulating blood, nor intravascular 

 hemolysis in the living subject as might have been expected in the 

 presence of hemolytic toxin. Examining gangrenous muscle they 

 reported that the normal toughness and elasticity had been lost. It 

 could readily be crushed between the fingers or smeared out on a 

 plate. Microscopically recognizable muscle-fibres had fallen apart, 

 tending to break-up into short lengths. A considerable amount of fat 



*On the other hand, an alternative possibiHty is suggested by the observations, 

 and discussions of Butler (1945). The CI. welchii strains causing severe gas gangrene 

 in men may have invasive properties unassociated with toxin production but con- 

 nected with the bacterial cell. If such is the case, and since Butler finds large capsules 

 associated with those strains causing severe infections, then perhaps for complete 

 therapy of gas-gangrene antibacterial passive immunity as well as antitoxic immunity 

 should be employed. 



