422 A MANUAL OF BACTERIOLOGY 



to set up tetanus on inoculation, while if the same washed 

 bacilli be injected, together with a little lactic acid, tetanus 

 follows, the explanation being that the bacilli are unable 

 to multiply unless the surrounding tissues are damaged 

 and phagocytosis is prevented. The associated organisms 

 in the wound probably effect this, and do not act by 

 producing a condition of anaerobiosis as has been suggested. 

 Semple x has recently found that tetanus spores are occa- 

 sionally present in the human intestinal tract (Hamilton 

 suggested that tetanoid organisms in the intestinal tract 

 might be the cause of the so-called idiopathic or rheumatic 

 tetanus). He injected guinea-pigs with washed spores, 

 and tetanus did not ensue, but the tissue at the site of 

 inoculation, examined five to seven months later, still 

 contained the living spores. Semple suggests that such 

 latent spores may in some instances be disturbed and 

 become active by the hypodermic or intra- muscular injec- 

 tion of quinine, owing to the tissue necrosis and inhibition 

 of phagocytosis produced by the drug. 



Toxins.- Cultivated anaerobically in broth, the tetanus 

 bacillus forms a most potent extra- cellular toxin, so that 

 if the culture be filtered through a porcelain filter, 0-001 c.c., 

 0-0001 c.c., or even 0-00001 c.c. of the filtrate is a fatal dose 

 for a guinea-pig. 



Tetanus toxin broth contains a tetanising substance, 

 termed tetano-spasmin, and also a haemolysin, tetano- 

 lysin. The toxin has a special affinity for nerve-tissue 

 (see p. 159). Injected into animals such as the mouse, 

 guinea-pig and rabbit, the toxin broth produces tonic, 

 not clonic, spasm and with small doses the muscles at or 

 near the seat of inoculation tend first to be affected, so 

 that the spine may be curved, the leg paralysed, etc. 

 (Fig. 48). 



By treatment with carbon disulphide, tetanus toxin 

 1 Sc. Mem. Gov. of India, No. 43, 1911. 



