MECHANICS AND USEFUL ARTS. 91 



supply the extract at sixteen shillings a pound. Each pound is 

 tlie equivalent of one hundred and thirty pounds of meat, and will 

 furnish broth for one hundred and twenty-eight men. The ex- 

 ti'act in its best state is absolutely free from fat or gelatine, and is 

 now used veiy largely in continental hospitals. 



The pi'ocess for preparing " extractum carnis," given in Lie- 

 big's " Familiar Letters on Chemistry," is as follows: Chopped 

 meat, deprived of all fat, is boiled for half an hour with eight or 

 ten times its weight in water, which suffices to dissolve all the 

 active ingredients. The decoction must, before it is evaporated, 

 be most carefully cleansed from all fat (which would become ran- 

 cid), and the evaporation must be conducted in the water-bath. 

 The extract of meat is never hard and brittle, but soft; and it 

 strongly attracts moisture from the atmosphere. The boiling of 

 the meat in the first instance may be carried on in clean copper 

 vessels ; but for the evaporation of the soup, vessels of porcelain 

 should be used. Liebig's j^rocess for making beef-tea is as follows : 

 Raw beef (recently killed) one-half pound, distilled water twenty- 

 two and one-half ounces, common salt fifty grains, dilute hydro- 

 chloric acid sixteen drops ; macerate the beef, chopped very fine, 

 in the water, etc., for an hour and a haK; strain ofl' through a fine 

 hair-sieve ; take two tumblers daily. 



The following letter from Baron Liebig is taken from the " Lon- 

 don Lancet " : — 



" Sir, — I see that rather contradictory views are expressed by 

 different English writers on the value of the extract of meat, some 

 taking it to be a complete and compendious sul:)stitute for meat, 

 whilst others assert that it has no nutritive value whatever. The 

 truth, as is usually the case, lies in the middle ; and as I was the 

 first who entered more fully into the chemistry of meat, I may be 

 allowed shortly to state the results of my investigations, as far as 

 the extractum carnis as a nutriment is concerned. 



"Meat, as it comes from the butcher, contains two different 

 series of compounds. The first consists of the so-called albumi- 

 nous principles (i. e., fibrin and albumen), and of glue-forming 

 membi-anes. Of these, fibrin and albumen have a high nutritive 

 value, although not, if taken by themselves. The second series 

 consists of crystallizable substances, viz., creatin, creatinin, sarcin, 

 which are exclusively to be found in meat ; further of non-erys- 

 tallizable organic principles and of salts (phosphate and chloride 

 of potassium) . All of these together are called the extractives of 

 meat. To this second series of substances beef-tea owes its flavor 

 and efficacy ; the same being the case with extractum carnis, which 

 is, in fact, nothing but solid beef-tea, — that is, beef-tea from which 

 the water has been evaporated. Besides the substances already 

 mentioned, meat contains, as a non-essential constituent, a vary- 

 ing amount of fat. Now, neither fibrin nor albumen is to he found 

 in the extractum carnis which bears my name ; and gelatine (ghie) 

 and fat are purposely excluded from it. In the preparation of the 

 extract, the albuminous principles are left in the residue. This 

 residue, by the separation of all solulde principles, which are 

 taken up in the extract, loses its nutritive power, and cannot be 



