40 



membrane, according to their situation and action. They are very 

 strong and fibrous, combining great strength, with Hghtness ; their 

 extreme strength being well illustrated by the every- day occurence 

 of slaughtered animals being suspended by their Achilles tendon, or 

 ham-strings. Tendons are brought into action by the middle or fleshy 

 part of the muscle, contracting and relaxing. To keep the muscles in 

 proper order, good grooming and regular exercise are highly necessary 

 — a profession in itself — as in training race-horses, &c. 



126. Involuntary or Non-Striated or Non-Striped Muscle 



consists of spindle-shaped cells, each with its own nucleus. The cells 

 are arranged in such a manner that they overlap, and are held together 

 by a small amount of intercellular cementing substance. They are most 

 commonly collected into bundles of varying size, which may cross each 

 other or interlace. Although involuntary muscle, as its name indicates, 

 is beyond the control of the will, it is none the less necessary that it 

 should be supplied with nerves. It is chiefly found in the walls of 

 hollow^ viscera, such as the stomach and intestines, the urinary bladder, 

 the uterus, &c., and also forms an important constituent in the 

 formation of the coats of blood-vessels. In the hollow viscera, the 

 muscular tissue is very pale, thus diff"ering materially in appearance 

 from the voluntary muscles of the body. The heart contains a form 

 of muscular tissue which is mvoluntary, but possesses a deep red 

 colour. 



127. Muscles and Tendons are subject to Injury and Disease, of 

 various kinds. Injury may be caused by Wounds, and these may 



be:— 



1. Incised ; i.e, clean cut, as with a sharp cutting instrument. 



2. Bruised or contused, when caused by severe blows or falls. 



3. Lacerated ; when the skin and flesh are torn by a foreign 



body, as by barbed wire or a cart shaft, &c. 



4. Punctured ; when made by a pointed object, as a prick 



or probe with thorns, or stabs with pitch-forks, &c. 



5. Gunshot ; from shot, bullets, &c. 



6. Poisoned ; from say, the use of arsenical sheep dip, wasp 



stings, snake bites, &.c. 



