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a device to tahe tbe place 

 of tbe Camera Xuciba in flDicrograpbij* 



By Henry G. Piffard, M.D. 



THE act of micrography, or the reproduction on paper of 

 images of minute objects seen through the microscope, may 

 be practised in various ways, of which the three following 

 are the principal : — 



I. — The observer studies the object on the slide, and, when he 

 thinks he has the outlines and details, or a portion of them, suffici- 

 ently impressed on his mind, withdraws his eyes from the tube, and 

 commits the mental picture to paper, using, of course, both eyes 

 in directing the movements of his pencil. Success with this presup- 

 poses a retentive memory and considerable skill as a draughtsman. 



2. — The observer, looking down 

 the tube in the usual way with one 

 eye — for convenience, the left — is, 

 after a little practice, enabled, by a 

 sort of auto-projection, to see an image 

 of the object on a sheet of paper by 

 the side of the microscope. The out- 

 lines of this image he traces with the 

 pencil, using the right eye to direct 

 its movements, the observation and 

 the reproduction being simultaneous. 



3. — By the aid of a camera lucida, 

 of which there are many different 

 sorts, a reflected or projected image is visible on the paper 

 with the eye that is at the same time occupied in directly observing 

 the magnified image of the object on the stage. In one of the 

 latest forms of camera lucida — the Abbe — this use of half the eye 

 for observing, and the other half for recording, is a reasonably 

 convenient method, if the observer's eye is approximately normal ; 

 marked myopia or hypermetropia, and still more pronounced astig- 



FiG. 4. — The author's drawing 

 prism. 



