Page:The New International Encyclopædia 1st ed. v. 10.djvu/453

* HYGIENE. 391 HYGINXJS. Oiygen Nitrogen Carbon dioxide. Expired air 16.40 79.19 4.11 From these figures it is seen that expired air contains over one hundred times more carbon dio.xide and nearly 5 per cent, less oxygen than ordinary atmosj>heric air. Experiments have shown that the average adult emits with ea<?h expiration 22 cubic inches of air; or, assuming 18 respirations a minute, 570.240 cubic inches or 330 cubic feet of air in 24 hours. In this total of expired air there is 14.52 cubic feet of carbon dioxide. This amount is increased with increase of physical activity. The figures of De Chaumont, which are generally accepted, show that there is 0.6 part of carbon dioxide per 1000 in the air of a closed and occupied space, or 0.2 part in excess of that in ordinary atmosphere. Burning of coal or illuminating gas adds to the impuritj-, and hence ventilation is essential. In public build- ings, such as those named, there should be three cubic feet of space per person in each room, after deducting from the total room-space the amount occupied by furniture and the bodies of the per- sons. (8) Prevention of Disease. This is a very largs topic, and necessarily bears close relation with personal as well as domestic hygiene. It includes notification of diseases to a health offi- cer; most of the activities of municipal depart- ments of health (see Health, Boards of) ; con- trol of streets and houses, and disposal of refuse (see DisiXFECT.KTs) ; control of disease entering our ports (see Quarantine) ; prophylaxis of special kinds against spread of disease (see Antitoxin: Serum Ther.py: V.ccination) ; cleansing of public vehicles, to which reference has been made, etc. Overcrowded and dark tene- ments are the most frequent causes of the spread of disease in a community. They keep alive the diseases of childhood — measles, scarlet fever, diphtheria, etc. — and are the most frequent hid- ing-places for the germs of tuberculosis. (9) Disposal of the Dead is regulated by sanitary laws, which provide, in cities, that undertakers shall obtain permits for removal of dead bodies, and proper disposition shall be made of them by burial or cremation. Public funerals in the case of contagious diseases are often forbidden, and hermetically sealed paskets are enjoined in such cases by many municipalities. Mental and Physical Hygiene. To regard the matter from another view-point, hygiene may be also divided into mental and physical. The former will necessarily include many questions that belong to the latter, for the healthy action of the mind depends to a great extent upon the health of the body. A sufficient amount of sleep ought to be taken to refresh the powers of the mind, as well as those of the body, and that sleep ought not to be much disturbed by dreams. Of course there are those whose occupation demands varied, sometimes excessive exertion, and who must be "a law unto themselves.' The great time for practically apjilying the laws of mental hy- giene is during the years of childhood and youth. The method of teaching the child should bo of the simplest, as well as of the most cou'prehen- sive character, and the periods shouM lie fre- quent during which its mind is completely re- lieved of all serious study, and allowed to come to a perfectly natural and passive condition by mirthful and affectionate enjoyment. The school- rooms should be conunodious, and well ventilated, and they should not be overcrowded. Too many studies should not be required, so that hours which should be given to recreation or sleep will not be occupied with laborious efiorts of study, which often do little more than produce a dis- turbed and unrefreshing sleep, and pervert or de- stroy the appetite for wholesome food. In the matter of school hygiene, great importance is attached to the amount, arrangement, and dis- tribution of light in the class-rooms; the con- struction of the seats and desks; the type and paper used in making the text-books, etc. Care- lessness in these matters is kno™ to be one of the most fruitful sources of imperfect sight, such as myopia, as well as of various deformities, especially spinal curature. Military Hygiene. This term is applied to the sanitarj- care of the soldier in camp and garrison, and while on the field. ^Military hy- giene embraces a consideration of: (1) The Se- lection of the Recruit, his exercise and training, his general development, and his mental and moral education. (2) The March in Campaign; the work done on the march, the equipment, rests, use of lluids. mental occupation, accidents, strain, and the general health of the troops. (See Marching.) (3) TVater /or Onii/viiiir, its purifi- cation and protection. (See Encampment.) (4) The Ration: its choice, amount, and variety; cooking of meals, disease as related to food, emergency or reserve ration, and travel ration. (See R.^tion.) (5) Military Clothing and Equip- ment (see Uniform, Military) ; head-covering, underclothing, disposition of the equipment. (6) Camp Rites, and Camps, with attention to soil, vegetation, shelter, and area, and their sanitary administration. (See Encampment.) (7) Posts, Barracks, and Hospitals. (See Hospitals, par. Militari/.) (8) Ventilation, Heating, and Light- ing. (9) Disposal of Excreta and Waste. (10) Personal Cleanliness of the SoUlier. (11) The Soldier's Diseases and Mortality. (12) Disinfec- tion. ( 13) The Habits of the Soldier as Affecting His Effxciency. (14) Climate, and Life on a Troop-Ship. (15) Disposal of the Dead. BlBLiOGR.^PHY'. WjUoughby, Hygiene for Stu- dents (New York, 1901): Harrington. Practical Hygiene (New York. 1901) ; Sedgwick, Sanitary Science, and the PuUic Health (New York, 1902) ; Hamer, Manual of Hygiene (London, 1902) : Munson. The Theory and Practice of Mili- tary Hygiene (New York, 1901). See Sanit.RT Science: Tubebcitlosis ; Heating and Venti- lation. HYGIENE OF FOOD. See Food. HYGI'NTJS, Oaius .Julius. A Latin author. He is generally suppo.sed to have been a native of Spain, though some writers claim that he was bom in Alexandria. Egjpt, and that he came to Rome with .Julius Cfcsar when a mere child. He is known to have been a favorite with Augustus, who made him chief librarian in the new Pala- tine Library. He was a voluminous writer on many subjects, including biography, agriculture, bee-keeping, and military" arts, as well as com- ments on the poems of Vergil and Cinna. These have all been lost. There are also two works still in existence that are assigned to him. one. a text- book on mvtholosv, entitled Falularum Liber,