HIS LIFE AND LABOURS. 187 



organisms which, if unchecked, destroy the best red 

 wines, are extremely sensitive to heat. A temperature 

 of 50 Cent. (122 Fahr.) suffices to kill them. Bottled 

 wines once raised to this temperature, for a single 

 minute, are secured from subsequent deterioration. 

 The wines suffer in no degree from exposure to this 

 temperature. The manner in which Pasteur proved 

 this, by invoking the judgment of the wine-tasters of 

 Paris, is as amusing as it is interesting. 



Moved by the entreaty of his master, the illustrious 

 Dumas, Pasteur took up the investigation of the diseases 

 of silkworms at a time when the silk-husbandry of 

 France was in a state of ruin. In doing so he did 

 not, as might appear, entirely forsake his former line of 

 research. Previous investigators had got so far as to 

 discover vibratory corpuscles in the blood of the diseased 

 worms, and with such corpuscles Pasteur had already 

 made himself intimately acquainted. He was there- 

 fore to some extent at home in this new investigation. 

 The calamity was appalling, all the efforts made to stay 

 the plague having proved futile. In June 1865 Pasteur 

 betook himself to the scene of the epidemic, and at once 

 commenced his observations. On the evening of his 

 arrival he had already discovered the corpuscles, and 

 shown them to others. Acquainted as he was with the 

 work of living ferments, his mind was prepared to see 

 in the corpuscles the cause of the epidemic. He fol- 

 lowed them through all the phases of the insect's life 

 through the eggs, through the worm, through the 

 chrysalis, through the moth. He proved that the germ 

 of the malady might be present in the eggs and escape 

 detection. In the worm also it might elude micro- 

 scopic examination. But in the moth it reached a de- 

 velopment so distinct as to render its recognition imme- 



