Wounds of Men who received Prophylactic Inoculation. 535 



Summary. — This Section of the investigation suggests that the serological 

 Type of the infecting bacillus may be of importance in relation to the patho- 

 genesis of tetanus in men who have received serum prophylaxis. Proof of 

 such relationship could, however, only be obtained by the investigation of a 

 large number of cases of the disease. Other methods of inquiry, therefore, 

 had to be undertaken. These are dealt with in Section IV of this com- 

 munication. 



Evidence of Geographical Distribution of Types of B. tetani. 

 When the first series of 14 toxic cultures was under examination, fighting 

 was especially heav}' in the northern portion of the British front ; and it was 

 during this period that Type II bacilli were recovered with the greatest 

 frequency. With the later fighting on the Amienois Sector, Types I and III 

 predominated. But shortly before the cessation of hostilities, when severe 

 fighting again occui-red in the northern area, the nimiber of Type II 

 infections again increased. These later cases are not included in the series 

 dealt with in this communication, as full details concerning them were not 

 available at the time of writing. 



Section II. 



Mechanism of Infection in Tetanus. 



In investigating this question, the following points were noted : — 

 (a) BacilH or spores deprived of their growth products by washing, or by 

 washing and heating combined, failed to produce the disease in susceptible 

 animals, even when injected in very large numbers — 2000 million in the case 

 of guinea-pigs and 200 million in the case of mice. 



(h) Tetanus toxin, when injected into rats in a sub-lethal dose, together 

 with vja-shed t-etanus bacilli, fails to induce the growth of the organism. 

 The aggressive qualities, therefore, of tetanus toxin, as ordinarily prepared, 

 are not marked. In this respect the pathogenesis of tetanus differs con- 

 siderably from that of gas gangrene. 



(c) When the toxin of B. Welchii is inoculated into animals in much less than 

 the lethal dose, together with the spores of B. tetani, it does not determine 

 the development of these spores, and therefore the onset of tetanus. 



The same may be said with regard to the toxin of Vihrion septique, but the 

 results are not so constant. 



Serum which is anti-toxic to the products of B. Welchii will, in such 

 circumstances, prevent the development of tetanus infection — if used 

 .sufficiently soon after the administration of the infecting inoculum. 



(d) Somewhat unexpected results were obtained when chemical irritants 



