For the disinfection of walls in stables and barns, common thin _white wash_ Ca(OH)_{2} is admirably adapted if made from freshly-burned quick lime. It possesses strong germicidal powers, increases the amount of light in the barn, is a good absorbent of odors, and is exceedingly cheap. Carbolic acid, creosote, and such products, while excellent disinfectants, cannot well be used on account of their odor, especially in factories. For gutters, drains, and waste pipes in factories, _vitriol salts_ (sulfates of copper, iron and zinc) are sometimes used. These are deodorants as well as disinfectants, and are not so objectionable to use on account of their odor. These suggestions as to the use of chemicals, however, only apply to extreme cases and should not be brought into requisition until a thorough application of hot water, soap, a little soda, and the scrubbing brush have failed to do their work. FOOTNOTES: [51] Guenther and Thierfelder, Arch. f. Hyg., 25:164, 1895; Leichmann, Cent. f. Bakt., 2:281, 1896; Esten, 9 Rept. Storrs Expt. Stat., p. 44, 1896; Dinwiddie, Bull. 45, Ark. Expt. Stat., May, 1897; Kozai, Zeit. f. Hyg., 38:386, 1901; Weigmann, Hyg. Milk Congress, Hamburg, 1903, p. 375. [52] McDonnell, Inaug. Diss., Kiel. 1899, p. 39. [53] Kayser, Cent. f. Bakt. II. Abt. 1:436. [54] Treadwell, Science, 1894, 17:178. [55] Conn, 5 Rept. Storrs Expt. Stat., 1892, p. 396. [56] Fermi, Arch. f. Hyg., 1892, 14:1. [57] Duclaux, Le Lait, p. 121. [58] Duclaux, Principes de Laiterie, p. 67. [59] Guillebeau (Milch Zeit., 1892, p. 808) has studied over a dozen different forms that possess this property. [60] Ward, Bull. 165, Cornell Expt. Stat., Mch., 1899; also Bull. 195, Ibid., Nov., 1901. [61] Adametz, Landw. Jahr., 1891, p. 185. [62] Marshall, Mich. Expt. Stat., Bull. 140. [63] Milch Zeit., 1899, p. 982. [64] Duclaux, Principes de Laiterie, p. 60. Heinze and Cohn, Zeit. f. Hyg., 46: 286, 1904. [65] Bull. 128, Wis. Expt. Stat., Sept. 1905. [66] Freudenreich, Landw. Jahr. d. Schweiz, 1896, 10; 1. [67] Weigmann, Milch Zeit., 1890, p. 881. [68] Conn, 3 Rept. Storrs Expt. Stat., 1890, p. 158. [69] Freudenreich, Fuehl. Landw. Ztg. 43: 361. [70] Harrison, Bull. 120 Ont. Agr'l. Coll., May, 1902. [71] Milch Zeit. 22:569. [72] Marshall, Bull. 146, Mich. Expt. Stat., p. 16. [73] Grotenfelt, Milch Zeit., 1889, p. 263. [74] Menge, Cent. f. Bakt., 6:596; Keferstein, Cent. f. Bakt., 21:177. [75] Heim, Arb. a. d. Kais. Gesundheitsamte, 5:578. [76] Adametz, Milch Zeit., 1890, p. 225. [77] 12 Rept. Wis. Expt. Stat., 1895, p. 148; also Bull. 67, Ibid., June, 1898. CHAPTER V. RELATION OF DISEASE-BACTERIA TO MILK.