DUST AND DISEASE. 291 



corpuscles infallibly appear, offering no difficulty of detec- 

 tion. This was the first great point made out in 1865 by 

 Pasteur. The Italian naturalists, as aforesaid, recom- 

 mended the examination of the eggs before risking their 

 incubation. Pasteur showed that both eggs and worms 

 might be smitten and still pass muster, the culture of such 

 eggs or such worms being sure to entail disaster. He made 

 the moth his starting-point in seeking to regenerate the race. 

 Pasteur made his first communication on this subject to 

 the Academy of Sciences in September, 1865. It raised 

 a cloud of criticism. Here, forsooth, was a chemist rashly 

 quitting his proper metier and presuming to lay down the / 

 law for the physician and biologist on a subject which was 

 eminently theirs. " On trouva etrange que je fusse si peu 

 au courant de la question ; on m'opposa des travaux qui 

 avaient paru depuis longtemps en Italie, dont les r<sultats 

 montraient Finutilit^ de mes efforts, et I'impossibilit6 d'ar- 

 river a un resultat pratique dans la direction que je m'etais 

 engage. Que mon ignorance fut grande au sujet des re- 

 cherches sans nombre qui avaient paru depuis quinze an- 

 nees." Pasteur heard the buzz, but he continued his work. 

 In choosing the eggs intended for incubation, the cultiva- 

 tors selected those produced in the successful "educa- 

 tions " of the year. But they could not understand the 

 frequent and often disastrous failures of their selected 

 eggs ; for they did not know, and nobody prior to Pasteur 

 was competent to tell them, that the finest cocoons may 

 envelope doomed corpusculous moths. It was not, how- 

 ever, easy to make the cultivators accept new guidance. 

 To strike their imagination, and if possible determine their 

 practice, Pasteur hit upon the expedient of prophecy. In 

 1866 he inspected at St. Hippolyte-du-Fort fourteen differ- 

 ent parcels of eggs intended for incubation. Having ex- 

 amined a sufficient number of the moths which produced 

 these eggs, he wrote out the prediction of what would oc- 



