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THE GRAPHO-PRISM. 



accompanied by first-class drawings, sketches, illustrations, etc., 

 if they are to be considered bona fide, and which should be 

 strictly a chef d'oeuvre. I would therefore advise every practical 

 and expert microscopist, and particularly those who are not 

 skilled in drawing or sketching, and in the art of producing 

 microscopic illustrations, to make use of the Grapho-prism. 

 Especially would I advise students of practical histology, physi- 

 ology, pathology, pathological anatomy, bacteriology, embryology, 

 pharmacology, etc., to use the Grapho-prism hand in hand with 

 the microscope. If a student produces a careful drawing of the 

 object under microscopical consideration and examination, he will 

 certainly comprehend the subject more readily and fully than 

 would otherwise be possible. 



This method of using the microscope and Grapho-prism 

 combined together, I denominate Microscopy Duplex, in con- 

 tradistinction to the other mode of studying microscopy in its 

 simple form without the Grapho-prism, Microscopy Simplex. 



Fig. 23. — Oberhauser's Grapho-Prism. 



I will now make a few explanatory remarks concerning the 

 Camera of Oberhauser (Fig. 23), which is somewhat more compli- 

 cated than the others ; for this reason I will give more particularly 

 the details in regard to its practical application in microscopy 

 duplex. The ascending rays from the objective are totally 

 reflected through the large prism {d) into the horizontal arm {A). 



