14 ANATOMY AND PHYSIOLOGY. 



whereas, if it were an artery, the band must be tied below the 

 wound, for the tide would be going downwards, from the heart. 

 The humeral artery lies under this vein, which it is dangerous to 

 wound. Where the arteries end, the veins begin ; small at first, 

 but gradually enlarging, they are void of pulsation, and as the 

 force of the blood is not so strong in them, so their substance is 

 thinner. When the blood is forced upwards, valves are provided 

 to prevent its return ; and these open only one way, like valves in 

 pumps. The blood in the veins moves seven hundred times slower 

 than in the arteries. 



GLANDS. 



The glands have the office of straining from the blood various 

 fluids, as the bile, saliva, urine, &c. 



MUSCLES. ^ 



The muscles are those fleshy parts which perform the motions of 

 the body ; and these are acted upon by nerves, which are sur- 

 prisingly minute vessels, which pervade every part, and are the 

 immediate objects of sensation. The white part of a muscle is 

 called a tendon, which is composed of fibres, more compact and 

 in less space. 



SKIN. 



The body is covered with a skin of the most delicate net-work, 

 through the pores of which is discharged an insensible fluid con- 

 tinually ; the pores of the skin are so minute that a grain of sand 

 would cover 125,000 of these little funnels, which are incessantly 

 employed in carrying off a superfluous vapor from the blood. The 

 discharge from the skin is upwards of three pounds daily of ex- 

 crementitious fluid, and in quantity the evacuation by its pores 

 exceeds that of the urine. Hence the importance of keeping this 

 organ in a healthy state. 



Nature does not forget beauty in her operations, and what can 

 beautify our form more than the veins lying parallel to the skin, in 

 those parts most conspicuous to public view the pliant wrist, the 

 taper arm, they variegate with an inlay of living sapphire. They 

 spread vermillion over the lips, and plant roses in the cheeks 

 while the eye, tinged with glossy jet, or sparkling with cellular 

 blue, rolls in polished crystal. 



