68 THE MICROSCOPE. [May, 



A DEVICE TO TAKE THE PLACE OF THE CAM- 

 ERA LUCIDA IN MICROGRAPHY. 



By Henry G. Piffard, M. D., 



NEW YORK. 



The art of micrography, or the reproduction on paper of im- 

 ages of minute objects seen through the microscope, may be 

 practised in various ways. 



Some time since, it occurred to the writer that the practice of 

 micrography could be greatly simplified by adopting the principles 

 employed in ordinary projection, as used in connection with the 

 optical lantern, the projection microscope, photography, etc. It 

 was only a question of reflecting the projected image onto a piece 

 of drawing paper fixed in some convenient position. To this 

 end, I requested Bausch and Lomb to mount a right-angled re- 

 flecting prism with a short tube extending from one of its square 

 faces, this tube to be of such calibre that it could be inserted into 

 the microscope in the place of the eyepiece. From the other 

 square face a similar short tube extends, capable of receiving the 

 ocular and holding it firmly. 



When preparing to use this device the object is placed on the 

 stage, and focused in the usual manner. The microscope is then 

 brought to a horizontal position, the eyepiece is removed, and 

 the prism case put in its place, the ocular being inserted in the 

 short tube provided for its reception. The ocular should point 

 downward. The lamp or other source of light should then be 

 disposed in such a way that it properly illuminates the object to 

 be examined, it being expressly understood that no light shall 

 escape toward the observer except that which first reaches the 

 object. A Beck lamp is conveniently adapted to this purpose. 

 If a piece of drawing-paper is placed beneath the ocular, and the 

 room darkened, a brilliant image will be projected on the paper, 

 and its reproduction can be easily accomplished with a maximum 

 of rapidity and a minimum of discomfort. In guiding the pencil 

 the draughtsman uses both eyes, and his spectacles if needed, 

 and sits in whatever position he finds most comfortable. With a 

 proper lamp, and careful utilization of its light, this device gives 

 excellent results, with amplification up to four or five hundred 

 diameters. If a sensitive photographic plate be substituted for the 

 drawing-paper, an exposure of a few seconds will impress an 

 image that may be developed in the usual way. — New York 

 Medical Journ il. 



