48 THE M1CROSCOPIST 



which may be brought quickly into the axis of the instru- 

 ment. 



Object-finders. It is sometimes tedious to find a small 

 object on a slide, particularly with high powers, and a 

 number of contrivances, as Maltwood's finder, have been 

 proposed for this end. A very simple method, however, 

 may serve. Mark on the stage two crosses, one like the 

 sign of addition -f, and the other like the sign of multi- 

 plication x , and, when the object is found, mark the slide 

 to correspond with the marks below. If the stage be a 

 mechanical one it will be necessary to arrange it in the 

 previous position. 



Microscopic Photography. Many European experimen- 

 ters have succeeded in taking microscopic photographs, 

 but a great advance in this direction has been made under 

 the direction of the medical department of the United 

 States army at Washington. Lieutenant-Colonel Wood- 

 ward has succeeded in furnishing permanent records of 

 many details of structure, which exhibit the very perfec- 

 tion of art. In a work like the present a full account of 

 the apparatus and methods employed would be out of place. 

 Dr. Beale's How to Work with, the Microscope, and the re- 

 ports issued from the Surgeon-General's office at Wash- 

 ington, will give the details. 



CHAPTER IV. 



USE OF THE MICROSCOPE. 



Care of the Instrument. But little satisfaction will be 

 secured in microscopic work for any length of time with- 

 out scrupulous care of the lenses, etc., belonging to the 

 instrument, and habits of this kind should be early ac- 

 quired. When in frequent use the microscope should be 



