The objectives used by Dr. Woodward, throughout, were a 1/8-inch of Wales’s (new series), and a 1/16-inch immersion, of Powell & Lealand’s, especially produced for work with the camera. The magnification varied from 800 to 3,000 diameters, a frustule of _Grammatophora Marina_ magnified 2,500, and a scale of podura, marked 3,000 in my collection, are equal in definition to those taken by a high-angle 1/12-inch oil-immersion. Pathological specimens taken with lower powers are equally instructive, a section of epithelial cancer showing both nuclei and cells with distinctness. Dr. Maddox in 1864 was also experimentally engaged in the improvement of the processes of photography for the purpose of promoting the work of microscopists. His labours were attended with great success. To him we are indebted for the gelatine dry-plate process, which gave a remarkable impetus to photography in general. Dr. Maddox has, for a period extending over forty years, diligently and successfully cultivated and promoted micro-photography. Among other workers to whom we are indebted for improvements in micro-photography I may mention Wenham, Draper, Shadbolt, Highley, Koch, Sternberg, Pringle, Leitz, and Pfeiffer. Dr. Koch justly claims the credit of having extended the application of micro-photography to the delineation of bacteria. A series of instructive micro-photographs were published by him in 1877. The importance of the camera has become more manifest as the work of the bacteriologist has progressed. Koch strongly advocated micro-photography on the ground that illustrations, especially of bacteria, should be as true to nature as possible. Dr. Edgar Crookshank holds the same opinion, and in support of his views we have numerous illustrations of the bacteria given in his valuable “Text-book of Bacteriology.” But he does not disguise the truth that there are difficulties to be encountered, the first of which is owing to the fact that the smallest and most interesting bacteria can only be made visible in animal tissues by _staining_. This drawback has been very nearly overcome by the use of eosin-collodion. With this medium, and by shutting off portions of the spectrum by coloured glasses, Koch succeeded in obtaining photographs of bacteria, which were stained with blue and red aniline dyes. This method, however, introduced a disturbing element of another kind. Owing to the longer exposure required, the results were wanting in definition, attributable, it was thought, to vibrations of the apparatus produced by passing traffic, or by assistants moving about over the floor of the laboratory.