510 A MANUAL OF BACTERIOLOGY 



if no improvement is manifest after the first dose ; intra- 

 venous and intra-muscular doses may also be given, and 

 the latter should be continued so long as any symptoms 

 persist. There is little doubt of the superiority of intra- 

 thecal administration over all other methods. Intra- 

 cerebral administration was practised in the past, but the 

 intrathecal route is safer, easier, and as efficient. 



The chief value of tetanus antitoxin is, however, as a 

 prophylactic. In the War, the wounded did not receive 

 injections of antitoxin until the middle of October, 1914. 

 In September of that year the incidence of tetanus among 

 the wounded was 9 per 1,000, in November it fell to 2-3 per 

 1,000, and up to November, 1918, in only two months was 

 this figure exceeded (2-4 and 2-7 respectively) ; generally 

 the incidence per 1,000 was not more than 1-7, and was 

 frequently below this figure. Many of the cases received 

 only a single dose, but in June, 1917, it was ordered that 

 each man should receive at least four inoculations at 

 intervals of a week. 1 



For prophylaxis, 1,500 U.S.A. units should be given 

 as soon as possible after receipt of the wound. As the 

 incubation period of tetanus may be a month or more, and 

 as a dose of antitoxin does not immunise for more than 

 three weeks, a second dose, at least, should always be 

 given if possible. Lack of this precaution may lead to the 

 development of tetanus, local or general. Even if tetanus 

 does develop after a single prophylactic dose, it generally 

 tends to be mild. 



Clinical Examination 



The symptoms of declared tetanus are so obvious that a bacterio- 

 logical examination is not needed to establish the diagnosis. 

 (1) Prepare several smears of the pus or discharge, and stain 



1 Bruce, Prevention of Tetanus during the Great War (Research Defence 

 Society). 



