SERUM TREATMENT OF TETANUS 719 



tion with T.-A. will help them to get rid of the bacilli is still an open 

 question. 



The subcutaneous injection is recommended as the best method of 

 administration. There can be no doubt that, in many cases, a single 

 injection produces sufficient protection. Such persons are, as a rule, 

 those who have already been sensitized by diphtheria bacilli. For the 

 ordinary run of cases at least two injections should be given. The first 

 injection then plays the part of a sensitizer. Experience shows that 

 sensitization occurs after from ten to fourteen days, which makes it 

 necessary that the second injection should not be given until after an 

 interval of not less than ten days. 



In this country the subject has been studied by William H. Park and 

 his associates, who found that this form of active immunization gave 

 rise to decided antitoxin production in 22 per cent, of susceptible per- 

 sons. The interval between vaccination and the development of im- 

 munity was generally long as a rule, not less than two weeks. Under 

 conditions of exposure about 20 per cent, of those who failed to respond 

 were found to develop clinical diphtheria. 



The remedy has not been used sufficiently often to enable us to ex- 

 press an opinion as to its value. Behring believes that its proper use 

 may thoroughly eradicate diphtheria. Obviously, its preparation must 

 be very carefully controlled, and for the present it should be used only 

 in institutions where thorough studies of the blood of patients may be 

 made before and after immunization. 



The Schick Test. This consists of the intracutaneous injection of a quantity 

 of diphtheria toxin equal to one-fiftieth of the minimal lethal dose. I dilute this in 

 such a manner that this amount is contained in 0.05 c.c. According to Schick, one- 

 thirtieth of a unit or more antitoxin per cubic centimeter of blood is sufficient to 

 neutralize this amount of toxin. If the patient has less than this quantity of anti- 

 toxin, the toxin is not neutralized and acts as a local irritant, producing an area of 

 superficial inflammation. Therefore, this test is a measure of immunity in diphtheria 

 and is advocated for testing the members of families and institutions, where it prob- 

 ably suffices to immunize with antitoxin those who react positively. (See p. 609.) 



SERUM TREATMENT OF TETANUS 



Tetanus antitoxin was discovered by Behring and Kitasato in 1892. 

 Since then it has proved of great value in the prevention of lockjaw. 

 While, in general, authoritative opinions regarding its curative value 

 vary, the statistics and the individual experience of many investigators 

 of more recent years show quite conclusively that tetanus antitoxin does 

 possess curative value, and is of distinct aid in the treatment of tetanus,. 



