Louis Pasteur: His Life and Labours

everything. It indicated the existence of a mysterious scourge, the origin and nature of which could not be traced, but which was ready to fall upon all the establ

prize of 5,000 florins was offered by the Austrian Government in 1868, as a reward for the discovery of th

rom pébrine. The production of silk and the production of eggs was thus secured. To make sure that the eggs were pure it was only necessary to have recourse to the microscopic examination of the moths which had produced them. These observations might be made by women, by young girls, even by children. It was sufficient to crush up a moth in a little water, and to put a drop of this mixture under the microscope, to see the corpuscles clearly, if they existe

which he had witnessed during two successive years, and, at the same time, impatient to find the cause of the scourge, Pasteur, in the months of February, March, and Apr

e putrid with extraordinary rapidity, often within the space of twenty-four hours. Sometimes they were soft and flabby, like an empty, crumpled intestine. Consulting the authors who had written upon silkworms, Pasteur could not doubt that he had before his eyes a characteristic specimen of the disease called morts-flats, or flacherie. Not only were these worms free from all pébrine spots, but no corpuscles were to be found in any

ed by the last-mentioned disease came from eggs produced by parents free from corpuscles, and led on to reproducers also free from this parasite. On visiting a multitude of industrial cultivations, Pasteur discerned that what had passed in his own laboratory was of

filled with microscopic organisms; some motionless, resembling little rods or spores joined end to end, like strings of beads, others more or less active, flexible, endowed with a sinuous movement like that of the vibrios found in nearly all organic infusions in process of decomposition. Whence come these

lls of parenchyma, green granules of the chlorophyl of the leaf, and remains of the air-vessels of the plant. Through the action of the liquids secreted by the glands which line the integuments of the intestinal canal,

unction of such importance to a creature which in the space of one month passes from the weight of half a milligramme to that of five, six, seven, or even eight grammes! Pasteur proved that whenever a worm was attacked with flacherie, it always had, associated with the food in its intestinal canal, one or other of the microscopic organisms which are invariably to be met

r. The worms have presented the most beautiful appearance up to the time of climbing the heather. The mortality has scarcely been two or three per cent., which is nothing; the moultings have been effected in a perfect manner, when suddenly, some days after the fourth moulting, the worms become languid, crawling with difficulty, and hesitating to take the leaves which are thrown upon their hurdles. If some few have mounted on to the heather, they stretch themselves on the twigs, their bodies swollen with food which they cannot digest. Sometimes they remain there motionless till they die, or, falling, remain suspended only by their false feet. The

y a fog or by the morning or evening dew, which deposits on the leaf the germs suspended in a great mass of air;-these are so many causes calculated to diminish the activity of the digestive functions of the worms, and to produce in consequen

ltivator, 'ought to wear a simple garment, not lined. He must regulate the temperature of the spinning-house according to the sensation of heat or cold which he experiences; if he

, of the microscopic organisms which provoke fermentation in the mulberry leaves, especially the vibrios, retain their vitality for several years. The dust of a silkworm nursery infected by flacherie appears under a microscope quite full of cysts or spores of vibrios. These spores or cysts rest, like the sleeping beauty in the forest, until a drop of water falls upon them and awakens them into life. Deposited on the leaves

ore readily did he produce the first of these maladies, when he gave, as food, leaves polluted by the contents of the intestinal canal of worms which had died of the disease. As in the case of pébrine, the

ope it is possible to obtain information as to the health of the worms, the chrysalides, and the moths destined to produce the eggs. Every attention should be directed to the complete exclusion of ferments from the intestinal canal of the worms, and from the stomach-pouch of the chrysalides-a little pouch to which the intestinal

g 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 produced by moths the worms of which have mounted the heather wit