276 MICROBES AND TOXINS 



late, and it is on this account that the mortality in diphtheria is 

 still lo per cent, (or 14 per cent, in epidemics ; L. Martin). 



(2). There should be no fear of giving large doses : in fact 

 in bad throats large doses ought to be resorted to at once. 



(3). Intravenous injection is the most efficacious : it is 

 indicated in all serious cases. This holds good for all sera. 



There is said to exist still in certain minds a certain 

 scepticism as to the value of antidiphtheritic serum but it is 

 scarcely credible. The figures speak for thernselves. The 

 death rate from diphtheria in the Sick Children's Hospital in 

 Paris before serotherapy was about 50 per cent.; it has fallen 

 to 6 — 10 per cent., and would be much less if the children were 

 treated at the very beginning of the disease. 



The serum is used as a prophylactic against diphtheria in 

 schools, barracks, creches and hospitals : a dose of 5 — 10 c.c. 

 protects for about three weeks. 



Anti-tetanic Serum is an antitoxic prophylactic serum. 

 The serum furnished by the Pasteur Institute possesses an 

 activity such that xroVTrTj c.c. suffices to neutralize in vitro 

 100 lethaLdoses for a mouse.^ 



In human tetanus when the incubation is long and the 

 progress slow, the serum may check the extension, i.e., may 

 have a limiting effect. According to the figures collected by 

 Vallas the serum has lowered the death rate from about 75 

 per cent, to 45 per cent. The mortality remains about 70 

 per cent, in those cases where the incubation period is less 

 than eight days. 



' When tetanus toxin and a sufficient dose of antitoxin are injected at 

 different points of the body a minute quantity of toxin escapes neutraliza- 

 tion and induces a slight local tetanus which is always recovered from. 



It is possible to cure animals inoculated in the paw if the serum is 

 injected at the first appearance of symptoms : when the poison has reached 

 the nerve-centres the antitoxin is of no avail. Roux and Borrel had the 

 idea of bringing the antitoxin in direct contact with the brain so as to 

 prevent the poison reaching the centres. By intracerebral inoculation 

 they succeeded in curing a number of guinea-pigs which had manifested 

 tetanus and were therefore doomed to die. But they do not extend their 

 conclusions to other animals. In man the first symptoms of tetanus 

 affect always the medullary centres so that cerebral treatment has even less 

 hope of success than in the guinea-pig. 



