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ference between oyster soup and oyster stew is chiefly in the amount of oysters employed.
Green Turtle Soup.-A soup stock prepared as above described and flavored with pieces of green turtle is a very common dish.
Mock Turtle Soup.-A soup made in imitation of a turtle soup in which veal takes the place of turtle for flavoring is known as mock turtle soup.
Clam Soup or Clam Chowder.-This is a soup made of clams in the same way that oyster soup is made. When the clams are cut into small pieces and are in great abundance and when potatoes are used in large quantities in the mixture it is known as clam chowder.
Beef Extract. It is evident that a beef extract is only a soup or a soup stock specially prepared from beef. Beef extract first became known by the researches of the celebrated chemist Liebig, and has passed from a mere local preparation to an article which is important in commerce. Factories have been established in localities far removed from the principal markets of the world, but where cattle are extremely plentiful, as in South America, and the preparation of beef extract is carried on on a large scale, the meat of the animal being thrown away after the preparation of the extract. The method of preparing beef extract is practically that described for making a soup stock under pressure. Instead of using only the trimmings and refuse of the animal, however, usually the whole of the flesh is employed. The bones are sometimes used in the making of a beef extract. The sound, fresh meat is cut into small pieces and extracted under pressure as already described. After cooking and filtering the product it is brought, in vacuo, to a proper consistence. Meat extract is, therefore, simply a concentrated soup stock. It requires about thirty-four pounds of meat to yield one pound of concentrated extract, and this extract may be diluted for consumption so as to make from six to seven gallons of beef tea. The composition of the ordinary beef extract of commerce shows that it contains from 15 to 20 percent of moisture, from 17 to 23 percent of ash and from 50 to 60 percent of meat bases, that is, the soluble nitrogenous contents of meat. The bones and tendons are not used in making beef extract on account of the introduction of considerable quantities of gelatine into the material. Liebig does not recommend the presence of gelatine in beef extract because, being cheaper in quality, it is an adulteration of the genuine article, which should contain only the pure bases and not the gelatinous principle of the meat in the tendons and bones.
Character of Nitrogenous Bodies in Beef Extract.-When beef extract is prepared according to the Liebig method those nitrogenous bodies commonly known as meat bases are found in the concentrated extract. In a beef extract which contains a total of 9.28 percent of nitrogen the quantity. of nitrogen in the form of nitrogenous compounds which were found therein is as follows: Nitrogen in the form of soluble albumin,-trace; in the form
of albumoses,-1.17; in the form of peptone,-trace; in the form of meat bases, 6.81; in the form of ammonia compounds,-.47; in the form of unenumerated compounds,-.83. The chief meat bases which form the principal part of the substance are creatin, creatinin, xanthin, carnin and carnic acid.
There are many different forms of beef extract upon the market, sometimes called by fanciful names and sometimes by the name of the manufacturer. Among the fanciful names are some which indicate origin or kind. The extracts which bear the names of the manufacturers are very numerous, but all of these extracts are essentially of the same character. One of these is a meat extract in which some of the meat fiber is contained. The quantity of meat fiber which is used varies, but is not very great. A comparison of the dry substance in a preparation of the class mentioned above with the dry substance in meat shows the following relation:
MEAT BASES. ASH AND MINERAL MATTER.
The above data show that the extract is essentially different in its composition from dried meat and has added to it a large quantity of meat fiber or the meat rendered soluble by some kind of treatment.
Nutritive Properties.-It cannot be denied that meat extract, as has been said in the case of soup stock, contains only a small part of nutritive matter. This nutritive substance is in a state of solution and probably is more readily absorbed than a similar amount of other nutritives in the form of ordinary meat. Its chief value as a nutrient, therefore, is not in the amount of nutrient material which it contains, but in the ease and speed with which it may become absorbed into the circulation. In case of illness this is often a very important point. It is not a question so much of the utilization of a large amount of nutrients as the absorption and assimilation in small quantities which will sustain life until the disordered conditions disappear. For these reasons the meat extracts have a value. There is, however, little doubt of the fact that in the popular mind a great deal more credit is given to meat extracts than should properly belong to them. They must be regarded principally as condimental and incident to nutrition rather than as nutritive substances. The claims which are made by the manufacturers are sometimes misleading, as, for instance, that one pound of extract contains the nutritive properties of many pounds of meat. Such a statement, of course, is absurd upon its face and should not be allowed to go unchallenged. Even when meat extracts are reinforced by the addition of soluble or comminuted fiber, as is often the case, the quantity of nourishment is very small as compared with a similar weight of meat itself.
It is not intended by the above remarks to cast any discredit upon the value of beef extract, as its value has been attested in numerous cases. It is only designed to call attention to the fact that as food these extracts have comparatively little value. They may be useful as stimulants or as condimental substances or as a means of speedily introducing a soluble nutrient in the case of disease where it is extremely important that even small amounts of nutritious material should enter the body.
Beef Juice. A distinction is made between a beef extract and a beef juice. The latter term applies solely to the liquid naturally remaining in the fresh meat after its proper preparation for consumption, that is, after the withdrawal of the blood and the proper cooling and storing of the flesh. The fresh meat is then subjected to strong pressure and the juices which are extracted are concentrated in vacuo to the proper consistence. The meat of old bulls is often used. A true beef juice must be extracted from the cold meat and not with the aid of heat, hot water or other solvents. It is difficult to preserve an extract of this kind without sterilization, and the heat required for sterilization is likely to coagulate some of the albuminous material which is expressed. It is a great temptation, therefore, in some cases to preserve the beef juice by a chemical preservative other than common salt. Boric acid and sulfite of soda may be used for this purpose, but these substances are objectionable on the score of possible injury to health. Glycerine is also used. Inasmuch as these juices are usually given to invalids or those whose digestive functions are impaired it is most important that injurious substances should be omitted. In case of pressure it is advisable, in some cases, to chop the meat very fine, and in this comminuted condition extract the juice with cold water. This does not produce any change in the character of the juice and the water is subsequently removed by evaporation at a low temperature in vacuo. Beef juices are usually prepared from heated meats.
Composition of Beef Juice.-The composition of beef juice from different parts of meat which was previously heated externally is shown in the following table.
P2O, (phosphoric acid),
COMPOSITION OF BEEF JUICE AND MEAT EXTRACT.
Acid (as lactic),.
insoluble and coaguable,
The above analyses show the general character of meat juice extracted first by externally heating the meat and then pressing. They show that there is less nitrogenous bodies present in meat juice than there is in meat extracts. It is evident that meat extracts cannot be heated for sterilization without coagulation of the globulins. When it is advisable to use a beef juice in a case of illness it is far better to prepare it at the time when it is used than to prepare it on a commercial scale and preserve it by any of the chemical means in vogue. Meat juice can be very well prepared for domestic use by chopping the meat very fine, placing it in a vessel, heating to 140° F., and pressing it by any simple means, as, for instance, with the hand or by using an ordinary lemon squeezer. The juice obtained in this way can be flavored with salt and spices to suit the taste of the patient, and used immediately. In some cases, in order to get a greater yield, pure cold water may be mixed with the chopped meat and a somewhat dilute juice obtained but giving a greater yield of nutritive material for the same weight of meat.
Various names, fanciful and otherwise, are given to the so-called beef juices. These names are either fanciful or, as in the case of beef extracts, that of the manufacturer. Some of the fanciful names are, like those already mentioned, suggestive of origin. Some of these have large quantities of coagulable protein, like albumin, while others have such small quantities as to indicate that they are not wholly beef juice. In the case of some of these preparations there is some indication that they are prepared chiefly from blood and thus are not true meat juices. Naturally there must be particles of blood in a meat juice and the mere occurrence of blood cells would not be an indication that blood itself had been used in its preparation. By reason of these facts the use of so-called meat juices is restricted. They contain relatively very little nutritive material, they are sometimes preserved with harmful chemicals and they may be made from blood, and in general there is such a degree of secrecy attending their preparation as to warrant the physician and patient to confine themselves to the domestic article prepared at the time of using. Another objection which is not of a hygienic character is found in the great expense of securing a very little nourishment by this means. The quantity of juice which meat will yield is very small and, therefore, the relative expense for any given quantity of nourishment is far greater than it is even in the case of beef extract. While in the case of rich patients an objection like this is of little value, in the great majority of cases it should be given due consideration.
Soluble Meats.-Various attempts have been made to put soluble meats upon the market for use, especially for invalids and in cases of disordered digestion. The principle which underlies the preparation of these meats. is to subject them to a certain degree of artificial digestion, by means of which the protein matter becomes converted into soluble forms, either albumose,
proteose or peptone. The process which is employed is a simple one, namely, the comminution of the meat into as fine particles as possible and its admixture with hydrochloric acid and pepsin. It is then subjected to artificial digestion until a considerable portion of the meat is soluble. Another method of preparation is to omit the pepsin and after the addition of hydrochloric acid to place the meat in a digestor where it is subjected to a temperature of steam under pressure for a considerable length of time. A goodly proportion of the meat becomes soluble under this process. After the preparation is completed the residual hydrochloric acid is neutralized by carbonate of soda, forming common salt, which gives the proper flavor to the compound.
The composition of soluble meat prepared in this way is given in the following table (Foods and Principles of Dietetics, by Robert Hutchinson):
PREPARATION OF BLOOD.
A meat solution of this kind is not really a solution, since not only is that part which passes into solution contained in it, but also the residual meat fibers which are not dissolved but so softened by the process that they lose their distinct form and can be rubbed up to a thick pasty mass. The product, therefore, consists not only of the part of the meat rendered thoroughly soluble in water by the process, but also of a residual part, softened and reduced to a paste. The mass has practically the same nutritive value as an equivalent amount of meat with the claimed advantage that a large portion of it is already soluble. This partial predigestion may be of value in cases of disease or disordered digestion of any kind, but there is no reason for believing that the healthy stomach requires any sort of artificial predigestion for the proper conduct of its functions. On the other hand, there is every reason for supposing that any kind of predigestion which is at all effective will in the end prove injurious to healthy digestive organs by depriving them of a part of their normal functions and thus tending to bring them to a condition of feebleness which may result in the omission, in part, of the normal functions of the vital organs.
Preparations of Blood.-There is no doubt of the valuable nutritive properties of blood and its preparations are sometimes used as foods. There is a deep-seated prejudice against the use of blood as human food, doubtless based on older and more effective grounds than even the laws of health promulgated by Moses. Man is an animal of some refinement of character and the sight or use of blood is repugnant to his finer instincts. Sometimes blood is dried and powdered and the blood powder mixed with other food.