Essays on the floating-matter of the air in relation to putrefaction and infection / by John Tyndall.

  • Tyndall, John, 1820-1893.
Date:
1881
Catalogue details

Licence: Public Domain Mark

Credit: Essays on the floating-matter of the air in relation to putrefaction and infection / by John Tyndall. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    and adopted by Pasteur. Pebrine declares itself in the stunted and unequal growth of the worms, iu the languor of their movements, in their fastidiousness as regards food, and in their premature death. The course of discovery as regards the epidemic is this: In 1849 Gruerin Meneville noticed in the blood of silkworms vibratory corpuscles, which he supposed from their motions to be endowed with independent life. Filippi, however, showed that the motion of the corpuscles was the well-known Brownian motion ; but he committed the error of supposing the corpuscles to be normal to the life of the insect. Possessing the power of in- definite self-multiplication, they are really the cause of its mortality—the form and substance of its disease. This was well described by Cornalia; while Lebert and Frey subsequently found the corpuscles not only in the blood, but in all the tissues of the insect. Osimo, in 1857, discovered them in the eggs; and on this observation Vittadiani founded, in 1859, a prac- tical method of distinguishing healthy from diseased eggs. The test often proved fallacious, and it was never extensively applied. These living corpuscles first take possession of the intestinal canal, and spread thence throughout the body of the worm. They fill the silk cavities, the stricken insect often going automatically through the motions of spinning, without any material to work upon. Its organs, instead of being filled with the clear viscous liquid of the silk, are packed to distension by the corpuscles. On this feature of the plague Pasteur fixed his entire attention. The cycle of the silkworm’s life is briefly this: From the fertile egg comes the little worm, which grows, and casts its skin. This process of moulting is repeated two or three times at intervals during the life of the insect. After