74 



from almost ever}' utensil or article of horse furniture 

 found in almost every stable.* But on the mucous 

 membranes — and here my attacker had the chance of 

 displaying his knowledge — it has no more effect than 

 it would have on the tail-board of the cart behind the 

 horse, or than the vaccine virus has on the unbroken 

 skin of a child's arm. Only when the bacillus has 

 been placed in contact with subcutaneous or sub- 

 mucous tissues has it either any inducement or an}' 

 power to throw out its toxins and to produce the 

 intoxication known clinically as tetanus or lockjaw, 

 and it is only then that we can begin to discuss the 

 immunity or otherwise of the horse either as a class or 

 as an individual. Neither even does the bacillus 

 produce its intoxication in the same wa}^ as our septic 

 bacillus produces its i7ifection. The stray fact, there- 

 fore, which was so readily quoted, and which is pro- 

 bably known to most men, is seen to show no parallel 

 with anything I have said in relation to seplicsemia- 

 The question of immunity on the part of the individual 

 only steps in after the "certain conditions" have been 

 fulfilled, and not before. In the case of tetanus these 

 conditions are not ingestion ; in septicaemia of birds 

 they are. 



Critics also would do well to observe the " certain 

 conditions" which attach to the due and efficient per- 

 formance of their own functions : they are only two in 

 number — the first to know what the criticised is talk- 

 ing about, the second to realize what they themselves 

 are saying. 



{To be C07iti7nced). 



*Q. Siras Woodhead. Bacteria and their Products. 1891, page 22. 



