The lack of any satisfactory method of photographing living microscopic organisms in situ makes it seem desirable to publish the following simple method. It is one by which a microscopic preparation of the living organism can be made, which will allow the latter to be watched in its growth and photographed by transmitted light. It will be of service especially as applied to the higher bacteria and fungi where the manner of division, branching and spore-bearing is of importance, and its accurate registration desired.
The method is a combination of the hanging-block and the India-ink methods of demonstrating unstained bacteria. The blocks for this purpose are easily made by pouring melted glycerin agar on a microscopic slide to form a thin film, and retained by standing other slides on edge about the first. This will be found to be more easily handled than the film poured in a Petri capsule.