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CHAPTER VII. 



Practical Remarks on Microscopes for viewing and drawing 

 Aquatic Larva, fyc. 



By C. R. GORING, M. D. 



The instrument which I used in executing the drawings 

 was a single microscope mounted with three achromatic 

 lenses of the 9-10tb, 6-10th, and 2-10th of an inch sidereal 

 focus. Had I not possessed these, I should probably 

 have used sapphires, or even equivalent common ones ; 

 for I greatly prefer a single microscope as a drawing tool, 

 from its being so very handy and manageable, and taking 

 up so little room on the table. All the necessary mo- 

 tions were given to the optical part, and not to the stage, 

 in order that living objects should be disturbed as little 

 as possible. I always found it make a great difference 

 for the better when they were allowed to remain un- 

 moved, for their natural restlessness, when exasperated 

 by motion, renders them completely intractable ; when 

 undisturbed, they will sometimes remain quiet for half a 

 minute together. An aquatic live-box*, of a little larger 



See Plate, fig. 21. 



