Protective vaccinations 503 



and the prophylactic serum treatment is then of great service in 

 preventing the outbreak of the disease. 



Xetter 1 communicated to the Society of Pediatrics a summary 

 of 32,484 observations on the prophylactic injection of antidiphtheria 

 serum. Of this number 192 cases were noted in which the diphtheria 

 broke out in spite of the injections, corresponding to 0'6 per cent 

 of those treated. These figures, however, included all cases of the 

 disease which occurred up to thirty days after the injection. Now, 

 the immunity is often less durable than this, and it may disappear 

 more or less completely twenty days and sometimes even fifteen days 

 after vaccination. 



Xetter himself made great use of antidiphtheria vaccination. 

 It was his custom to propose to the parents either a protective 

 inoculation at once or a systematic precautionary bacteriological 

 examination of the throats of the children not yet attacked. He 

 regards the first method as preferable. According to the latest 

 statistics which he was kind enough to communicate to me, of 

 152 children (in 50 families), 91 of whom received protective inocu- 

 lations, not one contracted diphtheria : whilst in 239 other families 

 where the children had not been inoculated there were 52 cases of 

 diphtheria, with 10 deaths. Many practitioners in Paris have now 

 pronounced themselves in favour of protective injections of the serum, 

 and the Society of Pediatrics, at its meeting on llth June, 1901, 

 concluded the discussion of this question by proposing the following 

 resolution : " The Society of Pediatrics, affirming that protective 

 inoculations present no serious danger and confer a very considerable 

 amount of immunity for some weeks, recommend their use when 

 children are gathered together in numbers, and in families where 

 a scientific supervision cannot be maintained." 



The large amount of evidence collected on this question leaves no 

 doubt as to the real efficacy of vaccinations by antidiphtheria serum. 



The summary of the results obtained by vaccination in the 

 12 diseases of man and of animals I have just placed before my 

 readers cannot pretend to serve as a detailed guide to prophylactic 

 practice. My object has been merely to concentrate into one chapter [527] 

 the principal data upon which this very important question rests, to 

 bear witness to the progress which has already been realised, and at 

 the same time to show that the scientific study of immunity is in 



1 Bidl. Soc. d. Pediatr. de Paris, 1901, mai et juin. 



