[50] “British Medical Journal,” March 26, 1859; “Medical Times and Gazette” and “Popular Science Review,” 1862.
[51] “Parasitic Diseases,” “Journ. of the Royal Micros. Soc. of Lond.,” 1859-60.
[52] There are several other kinds of bacteria infesting milk, some of which are motile, others non-motile, producing acidity and colouring matter, as B. prodigiosus, red-milk; B. synxanthus, yellow milk; B. lactis aerogens, which are pathogenic; B. lactis albus, which coagulate milk; and another form, which is productive of slimy or ropy-milk.
[53] “Parasitic Diseases of the Skin,” 1859-73, p. 30. Bailliere, Tindal, and Cox.
[54] “Organic Germ Theory of Disease,” “Medical Times and Gazette,” p. 685, 1870.
[55] F. Cohn on the “Natural History of Protococcus pluvialis.”
[56] Pritchard’s “Infusoria,” p. 24, Plate I., 4th edition.
[57] In order to detect the presence of starch-grains in plants, the tissue must be kept in alcohol exposed to light, until the whole of the chlorophyll is dissolved out; it must then be treated for several hours in a strong solution of potash. After neutralisation with acetic acid, the tissue may be treated with iodine, which colours it blue, or with coralline solution, which colours it pink.
[58] Verhandl. d. Natur. Hist. Jahr. xx. p. 1. “Micros. Jour. Science,” vol. iii., p. 120.
[59] For instance, where the yellow Palmella is found the Chlorococcus will assume a yellow tinge in its soridial stage. Viewed by transmitted light the sori are seen as opaque balls, with an irregular outline.