I. Principal disease-ferments met with in wort and beer 6

II. Appearance under the microscope of the deposit from “turned” beer 20

III. TorulÆ in process of development 72

IV. Mycoderma vini functioning as an alcoholic ferment.—Right half, showing appearance of spores just sown; left half, their appearance after an interval of submerged life 116

V. Mucor, vegetating submerged, in deficit of air 136

VI. Ferment of mucor 138

VII. Yeast-cells—worn out and dissociated (left), after revival in a sweet wort (right) 148

VIII. Fertile mould-cells from the outer surface of grapes 152

IX. Various examples of the mode of growth of mould-cells from the outer surface of grapes 154

X. One of the ferments of acid fruits at the commencement of fermentation in its natural medium 166

XI. Saccharomyces pastorianus, in course of regular growth 168

XII. Ferment-cells from a spontaneous fermentation just starting 184