COMPOSITION OF ANIMALS AND OF FEEDING STUFFS 51 



fasciculus. These fasciculi, as stated in a previous paragraph (83), 

 are surrounded by connective tissue and united into larger fasciculi, 

 or bundles, each with its envelope of connective tissue, these bundles 

 again being united to form the individual muscles. The connective 

 tissue serves also to carry the blood vessels, nerves and lymphatics 

 with which the muscle is abundantly supplied, and, moreover, may 

 contain larger or smaller accumulations of fat. 

 Evidently, then, the muscle as a whole, and 

 even more the collective muscles making up 

 the lean meat of an animal, are far from consti- 

 tuting a homogeneous material. 



86. Composition of muscles. If the 

 term muscular tissue be limited to the 

 ultimate muscular fibers which are the ac- 

 tive agents in producing motion, consider- 

 ing the other structural elements of the 

 muscle as accessory, it may probably be 

 said in a general way that it consists essen- 

 tially of water, protein, meat extractives 

 and the various lipoids and electrolytes 

 found in greater or less amounts in all 

 protoplasm. But such a limitation of the 

 term muscular tissue, however rational from 

 an anatomical standpoint, is little suited 

 to the present purpose. In the nutrition muscle fiber. 

 of the animal, material is required to build 

 up the entire muscular system, with all 

 its accessory structures, and not merely for the production of 

 the muscle fibers, and we are concerned, therefore, with the 

 composition of the muscles as a whole i.e., of the lean meat 

 rather than with that of the ultimate muscle-fibers. 



Since, however, the lean meat contains a variety of tissues 

 aside from muscular tissue in the narrower sense connective 

 tissue, nerves, blood and lymph vessels, etc. (85), with more or 

 less of the fluid contents of the latter it is evident that its 

 composition is likely to be variable. Moreover, the lean meat, 

 especially of fat animals, contains a considerable and variable 

 amount of fat even after all the fat tissue which it is practicable 

 to separate mechanically has been removed. This fat, how- 

 ever, forms no part of the muscle proper but is simply a deposit 



FIG. 3. Part of a 

 (Hough 



