528 On a New Factor in the Mechanism of Bacterial Infection. 



such as has been observed in vitro. It is conceivable too that calcium salts 

 may directly interfere with phagocytosis and lysis, and experiments in vitro 

 will have to be carried out in order to test this point. But these factors, 

 even admitting for the sake of the argument that calcium salts did produce 

 these effects mi vivo, could only be accessory factors under the special experi- 

 mental conditions which involve the actual presence of calcium salts. When 

 a separation of the sites or times of the injections is made, the actual presence 

 of calcium salts can be excluded, but the phenomenon still makes its 

 appearance. 



Summary. 



The bacteria of gas gangrene {B. Welchii, Vibrion septique, and 

 B. osdematiens) and of tetanus, when completely freed from their toxins, 

 either by washing or by heating to 80° C. for half-an-hour, so that spores are 

 formed, do not produce the specific disease when injected into a mouse or a 

 guinea-pig. The normal animal disposes of the bacteria mainly by lysis and 

 partly also by phagocytosis, and this defensive mechanism is so eflficient as 

 to render these bacteria non-pathogenic when injected by themselves. 



If a small dose of a soluble ionisable calcium salt is injected together with 

 the bacteria or their spores, the specific disease is elicited in a very virulent 

 form. The chlorides of sodium, potassium, ammonium, strontium and 

 magnesium, when injected together with B. Welchii, are not capable of 

 producing gas gangrene. 



A direct contact between the bacteria and the calcium salt is not 

 essential. The phenomenon will occur if the bacterial suspension and the 

 calcium salt are injected at different times into the same site, or into 

 different sites at the same time or at different times. 



From these experiments and other experimental evidence the conclusion 

 is drawn that calcium salts, when injected subcutaneously, produce a local 

 change in the tissues at the site of injection. The effect of this change is to 

 bring about a local breaking down of the defensive mechanism against the 

 bacteria of gas gangrene and tetanus. The terms " kataphylaxis " or 

 " defence rupture " are proposed to designate this new phenomenon. 



Sterile watery extracts of earth are capable of producing this phenomenon. 

 They may owe this property in many cases entirely to the presence of 

 calcium salts, but there is evidence that in some cases the extracts of earth 

 owe their rupturing action to the presence of another chemical substance 

 or substances which have not yet been identified. 



The bearing of these observations on the etiology of gas gangrene and 

 tetanus is discussed. 



