10 THE FLOATING-MATTER OF THE AIR. 



que vous pouv^ez imaginer.' Pamphlets about the 

 plague had been showered upon the public, the mono- 

 tony of waste paper being broken, at rare intervals, by 

 a more or less useful publication. ' The Pharmacopoeia 

 of the Silkworm,' wrote M. Cornalia in 1860, 'is now 

 as complicated as that of man. Gases, liquids, and 

 solids have been laid under contribution. From 

 chlorine to sulphurous acid, from nitric acid to rum, 

 from sugar to sulphate of quinine, — all has been in- 

 voked in behalf of this unhappy insect.' The helpless 

 cultivators, moreover, welcomed with ready trustfulness 

 every new remedy, if only pressed upon them with 

 sufficient hardihood. It seemed impossible to diminish 

 their blind confidence in their blind guides. In 1863 

 the French Minister of Agriculture signed an agree- 

 ment to pay 500,000 francs for the use of a remedy, 

 which its promoter declared to be infallible. It was 

 tried in twelve different departments of France, and 

 found perfectly useless. In no single instance was it 

 successful. It was under these circumstances that M. 

 Pasteur, yielding to the entreaties of his friend, betook 

 himself to Alais in the beginning of June, 1865. As 

 regards silk husbandry, this was the most important 

 department in France, and it was the most sorely 

 smitten by the plague. 



The silkworm had been previously attacked by 

 vnuscardine^ a disease proved by Bassi to be caused by 

 a vegetable parasite. This malady was propagated an- 

 nually by the parasitic spores. Wafted by winds, they 

 often sowed the disease in places far removed from 

 the centre of infection. Muscardine is now said to 

 be very rare, a deadlier malady having taken its 

 place. This new disease is characterized by the black 

 spots which cover the silkworms ; hence the name pe- 

 brine, first applied to the plague by M. de Quatretages, 



