PRESERVING EGGS. 217 



to whom the so-called spontaneous stinking putrefaction of eggs 

 goes on in two ways. 



The first type is characterised by the albumin (white) changing 

 colour through whitish-grey to grey-green, and by the yolk becom- 

 ing gradually converted into a greasy, blackish-grey mass. At a 

 subsequent stage the yolk becomes mixed up with the albumin, so 

 that the entire contents of the egg form a pulpy ichor, smelling 

 strongly of sulphuretted hydrogen, which gas is not infrequently 

 produced in such quantity that the shell of the egg bursts with 

 a report. Of the organisms taking part herein, Zorkendorfer 

 isolated ten species, and distinguished them as Bacillus oogenes 

 hydrosulfureus a, /?, y, 8, e, f, >?, S, t, K, the first six of which 

 liquefy gelatin. 



In the second type of (bacterial) egg-putrefaction this gas is 

 not detected. Here the yolk and the albumin quickly coalesce 

 to form an initially thin, but subsequently pulpy, mass of a 

 pale ochreous-yellow colour, and with an odour like that of human 

 faeces. Zorkendorfer described five species of organisms causing 

 this decomposition, and bestowed on them the name of Bacillus 

 oogenes jluorescens a, /?, y, S, e. The first of these liquefies 

 gelatin, and they all elaborate a pale green pigment which imparts 

 a beautiful blue fluorescence to the medium. 



All these bacteria are exclusively aerobic, i.e. oxygen is essen- 

 tially necessary to their development. This needful gas obtains 

 access from outside, by passing through the eggshell, which is 

 well known to be permeable thereto, since otherwise the develop- 

 ment of the embryo chicken could not proceed. This necessity 

 for air on the part of the egg-putrefying Schizomycetes supplies the 

 explanation of the practice currently employed for preserving 

 eggs, viz., by simply immersing them in milk of lime, which not 

 only excludes air, but also by its disinfectant properties acts on 

 the organisms present on the eggshell and ready to penetrate 

 into the interior, killing some and restricting the development of 

 others. 



The aforesaid bacteria perish within the space of two days 

 when exposed to temperatures above 40 C., but at lower tempera- 

 tures and in damp air they develop rapidly. Bearing these facts 

 in mind, eggs could be preserved by keeping them for one or two 

 days at 50 C. and then storing them in a dry place, were it not 

 that the quality is thereby depreciated. If, then, steeping in milk 

 of lime is not determined upon, the eggs can be preserved by 

 coating them with lacquer or varnish after a careful cleaning. 



That bacteria penetrate through the unbroken eggshell has 

 contrary to an opposite opinion expressed by Gay on been 

 placed beyond doubt by the exhaustive researches of Zorkendorfer. 

 WILM (I.) showed that pathogenic bacteria are also capable of so 

 doing, cholera bacilli being found, in his experiments^ to pene- 

 trate to the interior of the egg within fifteen to sixteen hours. 



