

CHAP. xvin. VACCINATION A DELUSION. 297 



This being the case, it becomes really ludicrous to read 

 the questions and answers, and the serious discussions, 

 as to whether a " good vaccination " protects more or less 

 than a previous attack of small-pox. Some think the 

 protection is the same, but the greater number think it 

 is not quite so much. Even the most ardent vaccinists 

 do not claim a greater protection. But none of them 

 ever doubt the fact of the protection gained by having 

 had the disease, and yet none of them, nor any of the 

 Commissioners, thought that any evidence, much less 

 proof, of the fact itself was needed. They took it for 

 granted. " Everybody knows it." " Very few people 

 have small-pox a second time." ISTo doubt. But very 

 few people suffer from any special accident twice a 

 shipwreck, or railway or coach accident, or a house on 



goes more fully into the question, and arrives at the conclusion that 

 out of every 1000 cases of small-pox the probability is that ten will be 

 second attacks. Then by getting together all the European observa- 

 tions as to the actual number of second attacks during various 

 epidemics, the average is found to amount to sixteen in 1000 

 cases,, showing a considerable surplus beyond the number due to 

 probability. Further, the proportion of deaths to attacks has from 

 early times been observed to be high for second attacks ; and it has 

 also been observed by many eminent physicians whose statements are 

 given, that second attacks are more common in the case of persons 

 whose first attacks were very severe, which is exactly the reverse of 

 what we should expect if the first attack really conferred any degree 

 of immunity. 



Now the whole theory of protection by vaccination rests upon the 

 assumption that a previous attack of the disease is a protection ; and 

 Professor Vogt concludes his very interesting discussion by the 

 remark: "All this justifies our maintaining that the theory of 

 immunity by a previous attack of small-pox, whether the natural dis- 

 ease or produced artificially, must be relegated to the realm of fiction." 

 If this be the case, the supposed probability or reasonableness of an 

 analogous disease, vaccinia, producing immunity wholly vanishes. 



