242 SCIENCE PROGRESS. 



the dried moth is pounded in a mortar, and mixed with a 

 few drops of water. A drop of this is examined under a 

 microscope. If corpuscles are found, the cloth with its 

 little mass of eggs, is, along with the contents of the mortar, 

 thrown into the fire ; if there are no corpuscles present, the 

 eggs are kept to be hatched when the warm weather returns. 

 In this way worms, cocoons and moths free hom pe'brine are 

 obtained, and the disease is kept well under control. 



A second disease, Jiacherie, which was found to attack 

 weakly worms, was also traced to its source — the action of 

 microbes taken in along with the food, and setting up a 

 special series of fermentations in the alimentary canal. 



Speaking of the precautions to be taken in the selection of 

 silk-worms, Pasteur wrote : "III were a cultivator of silk- 

 worms, I would never hatch an egg produced from worms 

 that I had not observed many times during the last days of 

 their life, so as to make sure of their vigour at the moment 

 when they spin their silk. If you use eggs laid by moths 

 the worms of which have mounted the heather with agility, 

 have shown no traces of Jiacherie between the fourth moult- 

 ing and mounting" time, and do not contain the least corpuscle 

 of pebrine, then you will succeed in all your cultivations." 



The silk industry which at one time appeared to be on 

 the verge of extinction was restored to France, which in 

 consequence is to-day millions richer. The prolonged 

 strain and the work in the artificially heated cultivating 

 rooms, appears to have told upon Pasteur's health, and in 

 October, 1868, when still only forty-five, he broke down, 

 being seized with an attack of paralysis. One side only was 

 affected, but the effects remained to the day of his death. 

 The next year, however, found him again at work at Alais, 

 and then at the Villa Vincentina, near Trieste, on a silk 

 farm owned by the Prince Imperial, at which for ten years 

 the silk harvest had not brought enough to pay the cost 

 of eggs. Under Pasteur's direction the cocoons produced 

 "gave to the villa a net profit of 26,000,000 francs," or over 

 .£1,000,000 sterling ! All opposition had speedily to give 

 way before such a signal success, and Pasteur's method was 

 finally adopted by the silk-worm farmers of all nationalities. 



