216 president's address. 



aids to recovery, inasmuch as they lessen organic waste, and so 

 minimise the drain of nutriment, leaving more of it available for 

 that cell-proliferation which is essential to the destruction of the 

 invading microphytes. 



One of the most interesting points brought out by the study 

 of Bacteria is connected with the causation of the formidable 

 disease known as tetanus or lock-jaw. It is well known that 

 Bacteria of various kinds exist abundantly in earth, and especi- 

 ally in the superficial layers of soil : among these is found a 

 peculiar species of "drum-stick" shape, which has been shown 

 to be the active cause of tetanus. This bacillus occurs most 

 abundantly, it is said, in woods and cultivated gardens, but 

 appears to be somewhat capricious in its distribution. It is one 

 of the " anserobic" bacilli — that is to say, it grows only when 

 excluded from contact with the air ; and artificially it can be 

 cultivated only in an atmosphere such as that of hydrogen gas. 

 That tetanus can be produced by the insertion of particles of 

 bacilliferous soil beneath the skin of various animals has been 

 abundantly proved, and it has long been known that, in the 

 human subject, the injuries most likely to result in tetanus are 

 deep, penetrating wounds produced by such bodies as rusty or 

 dirty nails, or wounds into which foreign matters have been 

 roughly conveyed. In the one case the deep character of the 

 wound secures the absence of air, thus allowing the growth of 

 the organism ; in the other, the suppuration produced on the 

 surface of the bruised and disorganised tissues protects the 

 materies morhi by its purulent film from aerial contact. With 

 this information it is easy to account for such cases as the fol- 

 lowing — of which I have had personal knowledge: — A person 

 in paring the edge of a toe-nail produces an apparently trivial 

 wound between the side of the nail and the overlapping skin : 

 neglecting the ordinary precautions of cleanliness, and going 

 about as usual, the wound shortly inflames, tetanic symptoms 

 appear, and the patient dies. Again, a man is thrown violently 

 from a trap, alighting on his hands at the side of the road ; the 

 palm of one liaud is greatly bruised and lacerated, and tlie earth 

 of the road is inextricably driven in among the torn tissues, 



