1366 Journal of Applied Microscopy 



LABORATORY PHOTOGRAPHY. 



Devoted to methods and apparatus for converting an object into an illustration. 



AN IMPROVED PHOTO-MICROGRAPHIC APPARATUS. 



I have recently had constructed for Cornell Medical College a photo-micro- 

 graphic apparatus by B. & L., a description of which may be of interest to the 

 readers of the Journal, since there are certain departures from the regular type 

 of outfit. Some of these departures were suggested by me, but they were worked 

 out in detail and put into practical shape by the makers. To begin with, I will 

 point out the various alterations, all of which, I think, are improvements over 

 the old style, and afterwards proceed to describe the apparatus as a whole. 



In the first place, then, on the old plan the optical bench and camera stand 

 being practically all in one piece, the only way of finding the desired field for 

 photographing is to push the camera back in its bed and bend over to look 

 through the eye-piece. In this uncomfortable and back-breaking position it is 

 impossible to manipulate the slide except by means of one of those clumsy 

 mechanical stages which, though all very well for special purposes such as blood 

 cell counting, are not to be compared with one's fingers, which, after all, were 

 made at a much earlier date, for rapid manipulation. 



In a Zeiss camera stand which I had previously used, the steel rods on which 

 the camera moved could themselves be pushed back so that one could sit on a 

 stool between the optical bench and camera stand in order to find the field. The 

 chief objections to this plan are that the rods are apt to sag, and that the bench 

 and stand cannot be connected into one solid piece, making it difficult to preserve 

 the exact optical axis, or arrange a satisfactory method for mechanical focusing. 



Two years ago I saw at the Jenner Institute in London a photo-micrographic 

 outfit with a revolving optical bench, but had no opportunity of examining the 

 details or of finding out if the arrangement worked satisfactorily or not, since it 

 was entirely new. On mentioning the idea to llausch & Lomb, they suggested a 

 modification of one of their revolving microscopical tables. The details will be 

 described further on ; sufficient to say here, that by this arrangement I can sit 

 comfortably at one side of the apparatus and with my fingers manipulate the slide 

 on the microscope stage as easily as if I were sitting at an ordinary table. 



The camera stand has a connecting rod between its two cast iron supports, 

 just above their feet, and I then suggested that the rod be continued on to the 

 single upright of the revolving bench in order to give more rigidity, but was told 

 that so low down it would be of no use. After much discussion, it was decided 

 to have a rod connecting the upper parts of the uprights, and so made that it 

 could be put up and clamped in at the time of setting up the apparatus. This 

 seems a very satisfactory arrangement, undoubtedly adding to the rigidity and 

 helping to keep the optical bench and camera stand in optical axis. 



The next difficulty was how to manage for mechanical focusing. When the 

 bench and stand are fixed there is, of course, no trouble, since the focusing rod 

 can be prolonged under the fine adjustment of the microscope, but where the 

 bench revolves this prolongation of the rod must be got out of the way tempora- 



