IMMUNITY AGAINST TETANUS 431 



Behring recommended that for man a more powerful serum 

 should be obtained, namely, a serum of which one gramme would 

 protect 100,000,000 grammes weight of mice. 1 The potency is 

 maintained for several months if precautions are taken to 

 avoid putrefaction, exposure to bright light, etc. To this end 

 5 per cent, carbolic acid is usually added, and the serum is 

 kept in the dark. In a case of tetanus in man, 100 c.c. of 

 such a serum should be injected within twenty-four hours in 

 five doses, each at a different part of the body, and this 

 followed up by further injections if no improvement takes 

 place. Intravenous injection of the antitoxin has also been 

 practised, and, in cases which we have seen treated in this way, 

 has seemed to give better results than those obtained by the 

 subcutaneous method. The serum is warmed to the body 

 temperature and slowly introduced into a vein in the arm, the 

 pulse and respiration being carefully watched during the 

 proceeding. Ten to twenty c.c. can be injected every few hours, 

 and in all 100 c.c. should be given in as short a time as possible. 

 Henderson Smith has shown that when antitoxins to toxins of 

 the tetanus group are injected intravenously a high concentration 

 in the body fluid is maintained for some time, and the op- 

 portunity for neutralisation of toxin is thus great. He suggests 

 that both intravenous and subcutaneous injections should be 

 simultaneously practised. The former gives quickly the con- 

 centration which is desirable, and when the antitoxin injected 

 intravenously is beginning to be eliminated, that introduced 

 hypodermically comes into the circulation and the concentration 

 is maintained. The antitoxin has also been introduced intra- 

 cerebrally, very slow injection into the brain substance being 

 practised, but no better results have been obtained than by the 

 subcutaneous method. 



Many cases of human tetanus have been thus treated, but 

 the improvement in the death-rate has not been nearly so 

 marked as that which has occurred in diphtheria under similar 

 circumstances. As in the case of diphtheria, however, the 

 results would probably be better if more attention were paid 

 to the dosage of the serum. The great difficulty is that 

 usually we have not the opportunity of recognising the 

 presence of the tetanus bacilli till they have begun to manifest 

 their gravest effects. In diphtheria we have a well-marked 

 clinical feature, sore throat, which draws attention to the pro- 



1 The antitetauic serum sent out by the Pasteur Institute in Paris has a 

 strength of 1 : 1,000,000,000. Of this it is recommended that 50 to 100 c.c. 

 should be injected subcutaneously in one or two doses. 



