354 PHYSIOLOGY. 



Daily Excretions. Sweat, from 1.5 Ibs. to 4.5 Ibs. ; urea, about 

 1 oz. ; organic matter exhaled, 3 grains ; urine, 53 oz. 



" Of the entire excreta, 32 per cent pass off by the breath ; 17 per 

 cent by the skin ; 46.5 per cent by the kidneys ; 4.5 per cent by the 

 alimentary canal." CUTTER. 



Number of Sweat Glands. The number of sweat glands may 

 be as high as 3,500 in a square inch, and the average is estimated at 

 2,800 per square inch ; as there are about 2,500 square inches of body 

 surface, it is readily computed that there are several millions of sweat 

 glands. 



Number of Hairs on the Human Head. The average number 

 of hairs on the head is 120,000. They are set obliquely, and are con- 

 trolled by muscles so that they may be made to stand erect, or nearly so, 

 under the influence of certain emotions, as fear, anger, etc. 



Huxley and others have classified the races of men according to the 

 hair, into the Ulotrichi, or crisp or woolly haired division, including 

 the negroes, bushmen, etc. ; and Leiotrichi, or smooth-haired, sub- 

 divided into the Australioid, the Mongoloid, the Xanthochroic, and the 

 Melanochroic. 



In Europeans the hair is oval in cross-section ; in the Japanese 

 and Chinese it is circular. 



Circulation. Rate of blood flow : in the large arteries, from 12 to 

 16 inches a second ; in the caval veins, about 4 inches a second ; in the 

 capillaries, from 1 inch to 1.5 inches a minute. A portion of the blood 

 makes the complete circulation (in a horse) in less than half a minute. 

 This is found by putting some readily detected chemical into one jugular 

 vein, and noting how soon it appears in the other jugular vein. The 

 time necessary for all the blood to pass through the heart is estimated 

 as follows : Each ventricle pumps about six ounces of blood at each 

 stroke. At this rate thirty strokes, 25 to 50 seconds (or less), would 

 have pumped all the blood in the body. Still, some of the blood (from 

 the shorter circuits) may have been pumped twice, and some (from the 

 longer routes) may not yet have been around once. And since the 

 total amount of blood has been only approximately determined, these 

 figures are not very accurate. 



Number of blood corpuscles to the cubic inch, about 83,000,000. 



Dr. Tanner's Forty Days' Fast (Newspaper Account). No 

 Food but Water Taken. When Dr. Tanner came to New York 

 from Minnesota he weighed 184 pounds. He was six weeks making ar- 



