Louis Pasteur : his life and labours / by his son-in-law ; tr. from the French by Lady Claud Hamilton ; with an introduction by John Tyndall.

  • Vallery-Radot, René, 1853-1933.
Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: Louis Pasteur : his life and labours / by his son-in-law ; tr. from the French by Lady Claud Hamilton ; with an introduction by John Tyndall. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    When the worms of a cultivation have all spun their cocoons, they are smothered in a steam stove, and, after being dried in the sun, they are handed over to the spinners. If it is desired to reserve some of the cocoons for seed, instead of being smothered, they are strung together in chaplets. After about three weeks, the moth comes out of its chrysalis. It pierces the cocoon by means of a liquid which issues from its mouth, and which has the property of so softening the silk that the moth is able to pass through the cocoon. It has hardly dried itself and developed its wings when the males and females pair for several hours. Then the females lay their eggs, of which they can produce from fom' to six hundred. These are aU the phases through which silkworms pass in the space of two months. In the epidemic which ravaged the silkworm nm-- series in 1849 the symptoms were numerous and changeable. Sometimes the disease exhibited itself immediately. Many of the eggs were sterile, or the worms died during the fii'st days of their existence. Often the hatching was excellent, and the worms ar- rived at then- first moulting, but that moulting was a failure. A great number of the worms, taking little nourishment at each repast, remained smaller than the others, having a rather shining appearance and a blackish tint. Instead of aU the worms going through