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 PKOGKESS OF MICEOSCOPICAL SCIENCE. 



The Decomposition of Eggs. — In a paper lately read before the 

 British Association at Belfast, Mr. "William Thomson said that 

 researches on this subject were commenced by the late Dr. Crace Cal- 

 vert and himself about the beginning of October, 1870, and extended 

 over the following year and a half. From numerous experiments ho 

 drew the conclusion that whole eggs could only be attacked by one, 

 two, or all, of three different agencies of decomposition. The first, 

 which he termed putrid cell, is capable of being developed within 

 some eggs, no matter how effectually their shells be jjrotected by var- 

 nished coverings from the spores floating in the atmosphere. It is 

 generated from the yolk. In some cases the yolk begins to swell and 

 absorbs most of the white ; in others the yolk bursts, and its whole 

 substance becomes thoroughly mixed up with the white ; and in others 

 again it begins to change slightly, and then gives off minute cells 

 into the white, rendering the white turbid; but in all cases where this 

 takes thorough hold of the contents of the egg, true putrefaction com- 

 mences, and the albumen emits a putrid smell. The minute granules 

 or cells of the healthy yolk, when this decomposition commences, 

 assume a morbid vitality ; they grow large, and become filled with 

 small cells ; each large cell then bursts, and the smaller cells take 

 independent existence. These cells are the bioplasm of the yolk, 

 which, had the egg developed into a chicken, would have gone to form 

 its flesh, bone, and tissues. These cells, under their morbid vitality, 

 absorb oxygen, and liberate carbonic acid gas. Two eggs had their 

 shells well varnished over with shellac, and were set aside on a shelf 

 for one year, and both then opened. One appeared as fresh as on 

 the day when it was set aside, but when the other was struck with the 

 point of a knife to open it, the pressure of gas contained within the 

 shell burst out, and scattered part of its contents in all directions. 

 The next germ of decomposition — the vibrio — appears under the micro- 

 scope like a small rigid worm which swims about. These animalcules 

 are constantly found floating about in the atmosphere, but never pene- 

 trate into the contents of an egg if the shell be kept dry, but if the 

 shell be moistened or wet, the dried bodies of these animalcules 

 develop in that water, assume much vitality, and then penetrate the 

 shell and set up putrefaction. Eggs were placed in fluids swarming 

 with different animalcules, some like corkscrews, which swam by 

 quickly turning round ; others which appeared under the microscojje 

 like flukes, but which really had the form of an egg ; some with one, 

 some with two feelers, which swam by switching those feelers into a 

 quick serpentine motion in front of them. These, however, were not 

 able to penetrate the shell of the egg. The third is the fimgus decom- 

 position. The spores of this fungus are found everywhere floating in 

 the atmosphere. They settle on the shells of eggs placed in stagnant 

 atmospheres, and send myriads of filaments through the shell in all 

 directions, sometimes binding all sides of the shell together, in all 



