626 THE POPULAR SCIENCE MONTHLY. 



which has a faint smell of roast meat, is very good, and can be used 

 in the preparation of soups and broths. 



The meat-biscuit of Gail Borden is prepared by seething freshly- 

 killed beef with hot water till all the nourishing constituents are ex- 

 tracted. The solution of these constituents is then dried to the con- 

 sistency of an extract, and this is mixed w r ith flour into a dough which 

 is made into cakes and baked in a moderately hot oven. According 

 to Mr. Borden, five hundred grammes of the biscuit contain as much 

 nutritive matter as two and a half kilogrammes of fresh meat. In a 

 similar way, turnips, celery, spinach, and other vegetables, are dried 

 and compressed in square cakes, which, enveloped in tin-foil, will keep 

 fresh in the market for a very long time. 



Other methods of preservation depend on the use of antiseptics. 

 Besides carbolic and salicylic acids, borax, boric acid, boroglycerine, 

 and xanthogenate of potash, may be used in preserving. Aqueous 

 solutions of boric acid and borax are very effective preservatives, for 

 many months, of meats, fish, vegetables, or fruits, which are immersed 

 in them. Pulverized borax is also effective, whether by itself or mixed 

 with pulverized alum and gypsum. 



The substance called boroglycerine has recently attracted consid- 

 erable attention. With it Professor Barff has prepared meat for pre- 

 servation during long voyages, and has shipped experimental packages 

 of beef across the Atlantic Ocean and back without their undergoing 

 any change. Mr. Russell, President of the English Society of Arts, 

 has also, independently of Professor Barff, found it excellent for the 

 preservation of meat and milk. It promises to come into general use, 

 for its application is without the slightest danger to the healthful or 

 other qualities of the food, and it is very cheap. The " Deutschen 

 Industrie Zeitung " gives the following directions for its preparation : 

 Glycerine is heated to as high a temperature as it will bear without 

 decomposition, and as much crystallized boric acid is added to it as it 

 will dissolve. The usual proportion is 92 parts of glycerine to 62 

 parts of boric acid. The mixture is then heated to a temperature of 

 about 400, till after four or five hours the vapor of water ceases to 

 pass from it. The resultant product, after cooling, is boroglycerine, 

 in the form of a yellow, transparent mass, soluble in water and alco- 

 hol. It is applied to organic substances in solutions of one part to 

 forty parts of water. 



With xanthic acid, Professor Zollner, of Vienna, has preserved 

 beef and veal, poultry, pigeons, and over-ripe plums. Its operation is 

 the more effective because it is volatile at ordinary temperatures, and 

 a very small proportion of its vapor in the air of a chamber is efficient 

 to prevent all decay. 



A preservative salt, patented by a German manufacturer, consists 

 of crystallized boric acid and phosphate of soda, to which a mixture 

 of common salt and saltpeter is added. 



