536 Major W. J. Tulloch. Serological Types of B. tetani in 



were used to produce the necessary local tissue debilitation required to set 

 up tetanus infection. 



The chemicals used were — 



(1) lactic acid; (2) trimethylamine ; (3) saponine ; (4) calcium chloride. 



(1) Lactic Acid. — This gave very uncertain results. 



(2) Trimethylamine. — In certain concentrations this reagent, together with 

 the spores of B. tetani, not infrequently sets up infection in guinea-pigs, but 

 seldom does so in mice. , It was found that, in mice, the formation of a large 

 eschar resulted from the injection of this reagent in sufficient concentration, 

 together with 200 million tetanus spores, without, however, inducing tetanus, 

 although the eschar ultimately separated from the surrounding tissue. 



(3) Saponine. — This reagent, injected in certain concentrations together with 

 spores, invariably leads to fatal infection in guinea-pigs. In mice, on the 

 contrary, it fails to set up infection. 



(4) Calcium Chloride. — At the suggestion of Capt. W. E. Bullock, E.A.M.C., 

 attempts were made to study the influence of CaCl2 as an infection initiator in 

 tetanus. Notwithstanding the fact that CaCl2 leads to a much less obvious 

 disturbance than does, for example, trimethylamine, nevertheless it invariably 

 induces the development of B. tetani when injected along with spores. 



These observations indicate that the precise quality of the local " debility " 

 at the nidus of infection is a factor of great importance in the development of 

 B. tetani in the tissues. 



(e) Experiments were, therefore, set up to determine the relative importance 

 of the degree of tissue debiUtation on the one hand, and of the number of 

 spores inoculated on the other, as factors in the causation of tetanus. 



This inquiry showed definitely that, in experimental animals at least, the 

 degree of tissue debilitation is of much greater significance than is the number 

 of spores inoculated. 



Some of these experiments were extremely interesting. For instance, when 

 an insufficient degree of local disturbance was produced, typical local tetanus, 

 due to infection, was observed in certain of the animals (guinea-pigs were used 

 in this series of observations). From this they recovered. Similar cases of local 

 tetanus in experimental animals were also noted, even when the degree of tissue 

 debilitation was relatively great, provided that the animals had been passively 

 immunised with A.T.S. before or soon after inoculation with the " spore 

 debilitant" mixture. 



(/) The importance of the symbiotic factor — influence of the products of 

 B. Welchii, etc. — in the initiation of tetanus infection naturally led to the 

 question as to whether the infective capacity, or the toxogenicity, might not 



