DUST AND DISEASE. 295 



Pasteur describes in detail his method of securing 

 healthy eggs, which is nothing less than a mode of restor- 

 ing to France her ancient prosperity in silk husbandry. 

 And the justification of his work is to be found in the re- 

 ports which reached him of the application, and the unpar- 

 alleled success of his method, at the time he was putting 

 his researches together for final publication. In France 

 and Italy his method has been pursued with the most sur- 

 prising results. It was an up-hill fight which led to this 

 triumph, but opposition stimulated Pasteur, and thus, with- 

 out meaning it, did good service. " Ever," he says, " since 

 the commencement of these researches, I have been ex* 

 posed to the most obstinate and unjust contradictions ; but 

 I have made it a duty to leave no trace of these contests in 

 this book." And, in reference to parasitic diseases, he uses 

 the following weighty words : " II est au pouvoir de 1'homme 

 de faire disparaitre de la surface du globe les maladies par- 

 asitaires, si, comme c'est ma conviction, la doctrine des gene"- 

 rations spontanees est une chimere." 



Pasteur dwells upon the ease with which an island like 

 Corsica might be absolutely isolated from the silk-worm 

 epidemic. And, with regard to other epidemics, Mr. Simon 

 describes the extraordinary exemption of the Scilly Isles for 

 the ten years extending from 1851 to 1860. Of the 627 

 registration districts of England, one only had an entire es- 

 cape from diseases which, in whole or in part, were preva- 

 lent in all the others : " In all the ten years it had not a 

 single death by measles, nor a single death by small-pox, 

 nor a single death by scarlet fever. And why ? Not be- 

 cause of its general sanitary merits, for it had an average 

 amount of other evidence of unhealthiness. Doubtless, the 

 reason of its escape was that it was insular. It was the 

 district of the Scilly Isles to which it was most improb- 

 able that any febrile contagion should come from without. 

 And its escape is an approximative proof that, at least for 



