238 COMMON THINGS. 



be procured by the combustion of sulphur. Butchers' meat enclosed in 

 a vessel filled with this gas absorbs it and remains for a long time proof 

 against corruption. Oils, fats, syrups, &.c. and in general any thing that 

 will prevent contact with the air, may be used to prevent or retard the 

 putrefaction of boiled meats or fruits. Charcoal powder is also effica- 

 cious, as it excludes the air and condenses the oxygen. 



3. Putrefaction cannot proceed without a certain degree of heat. 

 Frozen meat, it is well known, may be preserved an indefinite length of 

 time, and animals enclosed in ice will remain unchanged for ages. — 

 Hence the efficacy of ice houses, cool cellars, &.c. in warm or temperate 

 climates. 



4. Moisture is the last essential to the putrefactive process, even 

 when the albumen of animal tissues is not coagulated if the moisture 

 is removed the tendency to decomposition is destroyed. Albumen dried 

 at a temperature of about 140° may be preserved for any length of time, 

 and may be redissolved with its valuable properties unchanged. The or- 

 dinary modes of preserving fruits, flesh, &c., depend for their efficacy 

 entirely upon the principal of removing the moisture. Meats, for ex- 

 ample, are brought in contact with salt which from its strong attraction 

 for water deprives them of their moisture or replaces it by a saline solu- 

 tion which is less liable to change. Sugar acts in a similar way in the 

 preservation of fruits, converting the water into an unchangeable syrup. 

 Dry charcoal powder newly calcined will also absorb moisture, and fur- 

 nish the means of preserving flesh for a long time. Alcohol preserves 

 animal substances by abstracting the water which is essential to putre- 

 faction. 



Specimens for cabinets are frequently preserved in alcohol, and ex- 

 perience has proved that the mode is efficacious, expense may be dimin- 

 ished by the use of any common liquor as gin or whiskey, which, with 

 the addition of a little creosote, can be made to answer well. 



It is said that water saturated with sulphurous acid will afford a 

 cheap, and with the addition of a little creosote, a very eflicacious sub- 

 stitute for alcohol. 



The ancient Egyptians used wood vinegar, which contains creosote, 

 in the process of embalming. 



We will conclude with a lew useful applications of the principles 

 that have been explained, for which we are indebted chiefly to Dr. Ure. 



Flesh may be preserved — 1. By cutting in thin slices, immersing in 

 boiling water, and drying at a temperature of 122°. 



2. By smoking. — The quality of the wood has an influence on the 

 smell and taste of the meat. Juniper and aromatic herbs impart their 



