1 66 TIIK PRESERVATION OF MEAT, ETC. 



less, occasionally originates at the horse-slaughterer's. As already explained in a 

 former chapter, we are indebted to the French confectioner APPERT (I.) for the 

 fundamental practical experiments made in connection with preservation by 

 steaming. In accordance with his process, the meat is boiled in any convenient 

 vessel, and pressed into tins. These are then closed, with the exception of a 

 small aperture, and placed in a bath of boiling water, the aperture being closed 

 by means of a little liquid solder, after steam has been given off for a short time. 

 Appert's successors subjected his process to numerous modifications, Fastier pro- 

 posing to heat the tins up to 110 C. in a bath of salt, and others recommending 

 additions of boracic acid, &c. Up to the present, no known antiseptic possesses 

 the dual property of, on the one hand, preserving flesh without depriving it 

 of valuable nutritive constituents or flavouring matters, and, on the other, of 

 having no injurious effect on health when the meat is eaten regularly. 



Inventors have been, and are still, particularly active in this field, and the 

 different processes for preserving meat that have been proposed are very numerous. 

 To report exhaustively on these would, however, far exceed the limits of the 

 present work ; any reader wishing to be more accurately informed on this subject 

 is referred to a comprehensive treatise compiled by PLAGGE and TRAPP (I.). 

 Instructions intended for practical use in the preservation of meat, fruits, 

 vegetables, &c., have been given by L. E. ANCLES (I.) and J. DE BREVAXS (I.). 



132. Preserving- Eg-g-s. 



The contents of the freshly laid eggs of birds, especially of poultry, are not in 

 all cases perfectly free from fungi. In refutation of a widespread assumption to 

 the contrary, it was shown by U. GAYON (II.) in 1875, and confirmed by O. E. R. 

 ZIMMERMANN (I.) in 1878, that the eggs, even of healthy birds, are exposed, even 

 during the time of their formation, to infection by bacteria. These organisms, 

 starting from the common anal duct of the bird, make their way into the ovary, 

 where they become mixed with the albumen of the embryo egg, and reproduce 

 themselves therein when the nutrient medium permits. The new-laid egg is 

 therefore already inhabited by bacteria, a circumstance that must be borne in 

 mind when it is desired to utilise raw eggs for the cultivation of bacteria, 

 according to the proposal made by F. HUEPPE (V.). 



The obnoxious decomposition not infrequently set up in eggs is generally 

 attributable to the development of these early intruders. Their pure cultivation 

 was first attempted by J. SCHRANK (I.), and then on a larger scale by C. ZORKKX- 

 DORFER (I.), according to whom the so-called spontaneous stinking putrefaction 

 of eggs goes on in two ways. 



The first type is characterised by the albumen (white) changing colour through 

 whitish-grey to grey-green, and by the yolk becoming gradually converted into 

 a greasy, blackish-grey mass. At a subsequent stage the yolk becomes mixed 

 up with the albumen, so that the entire contents of the egg form a pulpy ichor, 

 smelling strongly of sulphuretted hydrogen, which gas is not infrequently pro- 

 duced in such quantity that the shell of the egg bursts with a report. Of the 

 organisms taking part herein, Zorkendb'rfer isolated ten species, and distinguished 

 them as Bacillm oogenes hydrosulj wrens a, /5, y, d, e, , rj, 0, 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 albumen 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. ZiJrkendlirfer described five species of organisms 



iiig this decomposition, and bestowed on them the name of JBacilliis oogenes 

 fluoreacens o, /3, y, 5, *. The first of these liquefies gelatin, and they all elabo- 



