314 PUBLIC HEALTH BACTERIOLOGY 



large, to the other side via the commissure, and up the 

 cord to the higher centres. The latter extension can be 

 prevented by section of the cord. Lately, in India, the 

 relation between subcutaneous or intramuscular injections 

 of quinine (given for malaria) and the production of tetanus 

 has been worked out. Such quinine injections are apt to 

 have a destructive action on the tissues, and the foci of 

 dead tissue produced serve as suitable anaerobic media for 

 the growth of tetanus spores. The latter are believed to 

 reach these foci by absorption from the bowel. This 

 explanation will also probably serve for the Mulkowal 

 outbreak (1902), when 19 persons developed tetanus (out of 

 107 injected) after inoculations of Haffkine's plague 

 prophylactic. In India, tetanus spores seem to be present 

 in the bowel in a considerable proportion of the natives. 



Toxins. Broth cultures grown anaerobically are usually 

 highly toxic to animals, 0-000005 c.c. (0-00V0 o) or ^ ess Dem g 

 fatal to a mouse of 10 grm. weight. Fatal dose for a man 

 is given as 0-23 mgr., equal to 0-003 of a grain, or ^J^. 

 The maximum yield is given in 10- to 14-day-old cultures. 

 After this it rapidly deteriorates. This also happens after 

 separation from the bacilli by filtration, and in a few days 

 it may have only T i F of its original power. Von Behring, 

 who first noted this change, attributed it to the action of 

 light, temperature, and especially oxygen, on the toxins ; 

 and so such filtrates should be kept, covered with a layer 

 of toluol and in a dark cool place. Exposure for a few 

 minutes to 65 C. destroys it, as do 20 min. at 6o C. and 

 1-5 hour at 55 C. Drying has no effect apart from 

 temperature. It can be precipitated by over-saturation 

 of the solution with ammonium sulphate, and thoroughly 

 dried and stocked in vacuum tubes, together with anhydrous 

 phosphoric acid, it may be preserved indefinitely without 

 deterioration. The ordinary effects of the toxin are 

 attributed to " tetanospasmin." Besides this, a substance 

 named " tetanolysin " which has the power of destroying 

 the red corpuscles of various animals, was discovered 

 by Ehrlich. Tetanus toxin can be fully neutralized by 

 mixing it with brain substance. 



Tetanus toxin is peculiar in that, after introduction into 

 an animal's body, a definite incubation period occurs 



