518 Messrs. W, E. Bullock and W. Cramer. On a New 



In all the experiments mentioned so far, the bacteria or their spores 

 have been injected suspended in the various salt solutions. This direct 

 contact between the bacteria and the calcium salts gives the most 

 favourable conditions for the phenomenon which we have described, but it 

 is not essential. It has been possible to produce gas gangrene in mice by 

 injecting the spores of Vibrion septique and calcium salts either at the same 

 site at different times, or secondly, at the same time at different sites, the 

 injection of calcium salts either preceding or following that of the spores. 

 Similarly, tetanus has been produced by injecting the spores and the 

 calciiun salt at different sites at the same time and also by injecting calcium 

 salts and tetanus spores at the same site but at different times, the injection 

 of spores also either preceding or following that of the calcium salts. In 

 such an experiment, for instance, no tetanus occurred for seven days in mice 

 which had received an injection of tetanus spores. But, when, on the 

 seventh day, calcium chloride was injected tetanus developed on the follow- 

 ing day. 



These experiments, in which the injections of calcium salts and of bacteria 

 were separated in time or in space, throw light on the mechanism by which 

 the peculiar effect of calcium salts, with which this paper deals, is brought 

 about. A detailed consideration of these experiments will be given below in 

 dealing with the probable explanation of the phenomenon. 



On the Etiology of Gas Gangrene and of Tetanus. 



We have referred in the introduction to the fact that infection with the 

 bacteria of gas gangrene' and of tetanus is not in itself an adequate explana- 

 tion of the specific diseases produced by these bacteria, and that it was 

 necessary to postulate the existence of an accessory factor. The question 

 which naturally suggests itself is whether the phenomenon which we have 

 described in this paper represents this accessory factor. 



It has always been realised that both tetanus and gas gangrene are 

 diseases particularly associated with earth, and, in fact, these diseases can 

 be produced by injecting emulsions of earth into mice or guinea-pigs. The 

 explanation which is generally accepted is that the soil contains the spores of 

 the specific bacteria. No specific action is credited to the earth itself ; it is 

 supposed to act as a foreign body like many other things, such as pieces of 

 cloth, or splinters of wood, the presence of which is assumed to create an 

 exceptionally favourable nidus for the growth of the bacteria. As stated in 

 the introduction we have failed to find any experimental evidence which 

 would support the nidus theory. Vaillard,* who investigated in great detail 

 * Vaillard et Eouget, ' Annales de I'Instifcut Pasteur,' vol. 6, p. 385 (1892). 



