ANIMAL FOODS. 189 



around the muscular fibres fat is nearly always to be found. Meat, 

 therefore, also contains members of the proteid group, carbo-hydrate and 

 fatty food-stuff's, together with a considerable amount of inorganic salts. 

 Hence, meat is also an excellent food. Albuminous bodies are in greatest 

 amount ; then come the fats, then the carbo-l^drates, and finally the 

 different salts. Ordinarily lean meat may be said to c'ontain an average 

 of 73.5 per cent, of water, 26.5 per cent, of solids (of which 21 per 

 cent, is albuminous and 1.5 per cent, gelatinous, 1.5 per cent, fats, 1 

 per cent, carbo-hydrates, and 1 per cent, inorganic salts). Of the latter, 

 three-fourths consist of acid phosphate of potassium, one- seventh of earthy 

 phosphates and iron, and about one-fifteenth of potassium chloride. The 

 flesh of different animals differs in composition, as is shown by the 

 following table : 



In 100 parts Flesh. Ox. Calf. Pig. Horse. Chicken. Fish (Pike). 



It is thus seen that meat is especially distinguished by its high albu- 

 minoid constituents, which amount to four times that contained in milk. 

 Chicken-flesh and that of other birds is richer in albuminoids than that 

 of mammals, while the flesh of fish is poorer, though even here 18 per 

 cent, of albuminous bodies is present. Meat alone forms the food of the 

 carnivora onty, and, as we shall find that carbo-hydrates may be developed 

 from the decomposition of albuminoids, carnivorous animals will, there- 

 fore, require an immense amount of albuminous bodies, and therefore a 

 very great volume of meat. If carbo-hydrates are added to the meat 

 diet of the carnivorous animals the volume of the latter ma} T be very 

 considerably reduced and still the animal preserve its nutritive equilib- 

 rium. In a diet of raw meat animals always run a risk of taking entozoa 

 or parasites, such as trichina, into their interior. The preparation of 

 meat by prolonged boiling destroys all the parasites, and therefore serves 

 to render even infected meat harmless. When meat is placed in cold 

 water the inorganic salts and a certain part of the albuminous bodies 

 (about 3 per cent.), together with the so-called extractives of meat, 

 such as kreatin, xanthin, and hippoxanthin, pass into solution along 

 with small amounts of lactic acid. When the water is warmed up to 

 45 C. a certain amount of soluble albuminoids undergo coagulation and 

 form coaguli, M r hich float on the surface of the water. As the tempera- 

 ture of the water is increased the external surfaces of the meat first un- 

 dergo coagulation, and so prevent further escape of the muscle-juices. 

 Meat which has been subjected to prolonged boiling thus preserves a 



