744 GENERAL THEEAPEUTIC MEASURES 



become apparent until some time after the involvement of 

 the nervous system, and for this reason the use of tetanus 

 antitoxin is not so actively preventive at this period, when 

 the toxins have combined with proteid elements of the ner- 

 A-Qus system and are therefore unable to combine with and 

 be neutralized by the antitoxin. Nevertheless, tetanus anti- 

 toxin is of some value as a curative remedy in tetanus if 

 used within thirty hours of the beginning of the attack.* 



As a preventive agent when employed before infection, 

 or immediately after it, tetanus antitoxin is almost certain. 

 ISTocard injected 2,727 horses with tetanus antitoxin in a cer- 

 tain district, and while none of these developed tetanus, 

 there were 259 cases in the same region in unprotected 

 horses. The immunity produced by tetanus antitoxin is 

 thought to last from fifteen to thirty days. So-called idio- 

 pathic tetanus is in reality traumatic, resulting from small 

 unseen wounds of the mucous membranes or integument. 

 Tetanus antitoxin is then indicated for use in the horse 

 when the case is seen early, or as a preventive when tetanus 

 is prevalent,t or following wounds the character of which 

 (see above) suggests the possibility of the development of 

 the disease. The remedy may be employed without fear of 

 doing any damage if properly administered. There are three 

 ways of giving tetanus antitoxin; as a preventive it may be 

 given under the skin or intravenously, and, as a cure for the 

 disease, it may be used in these ways or be injected within 

 the brain. The latter method has been practiced consider- 

 ably in human medicine and with . somewhat uncertain re- 

 sults as compared with the intravenous injection, although 

 it is generally considered superior. Roux saved 35 out of 

 45 guinea pigs by intracerebral injection, whereas by sub- 

 cutaneous injection of antitoxin he had but two recoveries 

 in seventeen cases of tetanus. The injection is made with 

 a blunt needle into the substance of the brain through a 

 small hole in the skull made with a drill at a point midway 

 between the outer angle of the orbit and the centre of a line 



* Tetanus is fatal in proportion to the shortness of its incubation. 

 When antitoxin is given to cases having a short incubation there is little 

 , hope of its success. 



f In such localities it is wise to immunize animals against tetanus with 

 a dose of antitoxin before undertaking surgery (as castration) upon them. 



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