160 Animal Micrology 



at the eyepoint (see above) of the lens. This is some distance 

 from the eye-lens in low-power eyepieces, close to it in high- 

 power eyepieces. 



13. Put the microscope in its case when you have finished 

 using it, or at least cover it with a cloth or cone of paper. For 

 further details regarding the use or care of the microscope consult 

 one of the following books : The Microscope, by Gage ; Manipu- 

 lation of the Microscope, by Bausch; The Microscope and its 

 Revelations (1,200 pages), by Carpenter and Dallinger. 



14. Do not apply alcohol to any part of the instrument. The 

 lenses may be cleaned ordinarily by breathing upon them and 

 wiping them with a rotary motion on lens paper or a piece of soft 

 old linen. In case a solvent must be used for balsam or oil, ben- 

 zene is the one commonly recommended. It must be quickly 

 wiped away so that it will not affect the setting of the lens. Bits 

 of dust may be flecked off the surface of a lens by means of a 

 camel's hair brush. 



The beginner in microscopy should acquaint himself with 

 various common objects that are liable to get into his preparations 

 in the form of dust, etc., so that he may not mistake them for es- 

 sential parts of his specimen. Such objects are hairs, fibers of 

 silk, wool, linen, cotton, and the like, and particularly air-bubbles. 

 Air-bubbles are usually circular with black borders and bright 

 centers; they may show tinges of color. Examine a drop of 

 saliva for examples. 



