1. HARRINGTON, CHARLES H. Practical Hygiene, 5th revised ed. 2. ROSENAU, MILTON J. Preventive Medicine and Hygiene, 2nd ed., 3. 4. 5. 6. p. 796. BUSHNER. Centrlbl. f. Bakteriol. u. Parasitenk., xi, p. 781. CLARKE and GOGE. Public Health Reports, xxix, 386. 7. ROSENAU, MILTON J. Preventive Medicine and Hygiene, 2nd ed. NOTTER and FIRTH. Treatise on Hygiene. 8. 9. 10. FRANKLAND, PROF. PERCY. J. of the San. Inst., Oct., 1899, 393. HORROCKS, W. H. Bacteriological Examination of Water, London, 1901, 3. 11. MAYER, G. Centrlbl. f. Hyg. u. Infectionskrankh., 1899, xxi, 133. BIBLIOGRAPHY DON, T., and CHISHOLM, J. Modern Method of Water Purification, 2nd ed., New York, 1913, Longmans, Green & Co. HAZEN, A. Clean Water and How to Get It, New York, 1907, Wiley & Sons. MASON, W. P. Water Supply, 3rd ed., New York, 1902, Wiley & Sons. PRESCOTT, S. C., and WINSLOW, C. E. A. Elements of Water Bacteri ology, 3rd ed., New York, 1913, Wiley & Sons. Report of the Committee of the American Public Health Ass'n. Standard Methods of Water Analysis, 2nd ed., 1912. SAVAGE, W. G. The Bacteriological Examination of Water Supplies, Philadelphia, 1906, Blakiston's Son & Co. THRESH, J. C. The Examination of Waters and Water Supplies, 2nd ed., Philadelphia, 1914, Blakiston's Son & Co. TURNEAURE, F. E., and RUSSELL, H. L. Public Water Supplies, New York, 1907, Wiley & Sons. WHIPPLE, G. C. The Microscopy of Drinking Water, 3rd ed., New York, 1914, Wiley & Sons. For typical and composite analysis, see Annual Reports of the Massachusetts State Board of Health. Bulletin of the Illinois State Board of Health. The Municipal Water Supplies of Illinois, June, 1908, iv, 6. Bulletins of the United States Geological Survey Water Supply Papers. Some Working Analysis. CLARKE. The Data of Geochemistry, Chemistry and Physics, 54, U. S. Geological Survey, 1908, Bull. No. 330, Series E. DAVIES. On the Connection between Milk Supply and Disease, Providence Med. J., 1889. DEACON. The Constant Supply and Waste of Water, J. Soc. Arts, 1882, XXX, 738. DE RANCE. Water Supply of England and Wales, London, 1882. DOWNES, A. Diphtheria Communicated by Drinking Vessels, San. Rec., 1879-80, xi, 51. Enteric Fever Caused by an Overflow of Non-enteric Sewage into a Well, Lancet, April 27, 1872. DROWN. Interpretation of the Chemical Analysis of Water, Report on Water and Sewage to the Massachusetts State Board of Health, 1890. DUNBAR. Ueber den Typhus Bacillus und den Bacterium coli communis, Ztschr. f. Hygiene, 1892, xii, 485. DUPUIT. Etudes sur le mouvement des eaux, Paris, 1875. EKIN. Potable Water, London, 1890. EVANS. Our Homes, Cassell & Co., London, 1883, 807, 809. FANNING. On Hydraulic and Water Supply Engineering, New York, 1889. FARLOW. Supplement to First Annual Report of State Board of Health, Mass., 1877, p. 143. FARR. Report on the Cholera Epidemic of 1866 in England, Supplement to the 29th Annual Report of the Registrar-General, 1868. FIELD. Pollution of Well Water from Cemeteries, Trans. San. Inst., viii, 254. FLUGGE. Micro-organisms, New Syd. Soc., London, 1890. FRANKEL. Ueber den Bakteriengehalt des Eisens, Ztschr. f. Hyg., Bd. I. FRANKLAND, E. Water Analysis for Sanitary Purposes, London, 1880. FRANKLAND, P. Third Report to the Royal Society Water Research Committee, November, 1894. 1886. Multiplication of Micro-organisms, Proc. Roy. Soc., London, Recent Bacteriological Research in Connection with Water Supply, J. Chem. Industries, 1887. Hygienic Value of the Bacteriological Examination of Water, Trans. Internat. Cong. Hyg. & Demog., London, 1891. Experiments on the Vitality and Virulence of Sporiferous Anthrax in Potable Water, London, 1894. FREUNDENREICH. Ueber die Durchlässigkeit der Chamberländschen Fil- GIBB. Pollution of Cisterns by Sewage, Brit. Med. J., Oct., 1870. HARVEY. Food, Water, and Air, London, 1872, 68. HAWSLEY. Report of the Rivers Pollution Commissioners, vi, 233. HIRSCH. Geographical and Historical Pathology, translated by C. Creighton, M.D., 1886, iii, 340-343. HOCHSTETTER. Ueber Mikro-organismen im künstlichen Selterswasser, Arbeiten aus dem Kais. Gesundheitsamt, ii. LEFFMANN and BEAM. Examination of Water for Sanitary and Technical Purposes, London, 1895. MUSGRAVE and CLEGG. Bull. 18, Bur. Gov. Lab., P. I., No. 93. NICHOLS, A. H. The Contamination of Drinking Water with Impure Ice, Seventh Ann. Rep., S. B. H., Mass., 1876, p. 467. PARKES, L. C. Moorland Waters, Trans. Chem. Soc., 1899, lxxv, p. 196. PRESCOTT, S. C., and WINSLOW, C.-E. A. Elements of Water Bacteriology, 3rd ed., pub. by Wiley & Son, New York, 1913. RUSSELL, H. L. Public Water Supplies, New York, Wiley & Son, 1907. SAVAGE, W. G. The Bacteriological Examination of Water Supplies, pub. by Blakiston's Son & Co., Philadelphia, 1906. SEDGEWICK and WINSLOW. Experiments on the Effects of Freezing and THRESH, J. C. The Examination of Waters and Water Supplies, 2nd WHITELEGGE, A. B. Hygiene and Public Health. WOOD, HAROLD B. The Economic Value of Protecting Water Supplies, J. Am. Med. Assn., Oct. 2, 1909, p. 1093. CHAPTER XI THE MINERAL CONTENT OF THE BODY AND OF FOODS General Considerations: The Importance of the Mineral Salts; Mineral Mineral Content of Foods; Calcium; Magnesium; Iron; Sodium and Potas- GENERAL CONSIDERATIONS Importance of Mineral Salts.-The human body contains about seven pounds of mineral matter, of which five-sixths is in the bones. It is obvious from this that the mineral ingredients of the diet are important as building material for the human economy and are, therefore, to be regarded as foods. The principal minerals required in the food are sodium, potassium, calcium, magnesium, iron, with phosphorus, chlorin, sulphur, and traces of silica, fluorin, iodin and others. The mineral salts are indeed so necessary for maintaining the general metabolic balance of the body, that death would ensue within thirty days if the supply were stopped, even if all the other constituents of a normal diet were provided. The inorganic salts of the food are important as tissue builders, but of no consequence as sources of heat or energy because the salts in the foods enter the body in a form too highly oxidized to be capable of yielding any heat to the body tissues. The mineral salts are quite essential to nerve and muscle reaction, and it is due, directly, to their action that a well-balanced osmotic pressure is maintained. Their action favors absorption by increasing endosmosis of the tissues, thereby assisting metabolic processes. The metabolism of salts of the body plays a constructive part in the physiology of nutrition, and disturbances of this salt metabolism may be the cause of disease. Indeed Bunge has shown that the nitrogenous products of metabolism cannot be eliminated from the body unless mineral salts are present. The normal human body contains about 3,000 grains of sodium chlorid. The body requires daily about ten grams of this element and something like 180 grains is excreted daily through the urine, sweat, feces and tears. A practical illustration of the value of salt to animal life is observed by the regularity with which wild animals travel, sometimes great distances, to the so-called "salt licks." It is also interesting to note that among animals the herbivora require salt in their food, while the carnivora do not. Domestic animals will allow themselves to be caught for the sake of a handful of common salt. Whenever a high tax has been imposed on salt and its use restricted, the bealth of the people has suffered. In writing on this subject Bunge says: "Most vegetables are rich in potassium, which is ultimately eliminated in the form of mineral salts, largely as sulphate. Potassium sulphate in the blood reacts to some extent with sodium chlorid, forming potassium chlorid and sodium sulphate, both of which are rapidly eliminated by the kidneys. Hence the greater the amount of potash in the food, the greater the loss of sodium and chlorin from the blood, and the greater the necessity for salt to keep up the normal sodium chlorid content of the body." Bunge also believes that while man might live without the addition of salt to the food, even on a diet largely vegetarian, nevertheless, without salt he would soon experience a disinclination to eat much of the vegetables rich in potassium, such as potatoes, so that the use of salt tends to enable us to utilize a more varied selection of the earth's food products. Excessive use of salts probably acts injuriously by overstimulating the digestive tract, and may overtax the organs concerned in its elimination and thereby cause untoward symptoms. Under certain conditions even small amounts may be excreted in such quantity in the urine that they cannot be held in suspension and as a consequence are deposited in the urinary tract and cause the formation of concretions-"stones." Mineral Matter Contained in Excretions. The average amounts of the various mineral compounds excreted in the urine, feces and sweat are shown by the following table worked out by Gautier and other physiologists: |