HISTOLOGY. 15 



Handle the instrument with more than ordinary 

 care; never let anything touch the lenses. The in- 

 strument must be kept clean. Be careful and learn 

 to use the instrument with both eyes open. Do not 

 vise it so long that an aching sensation will be pro- 

 duced in the eyes. 



The accessories to the microscope are many, but we 

 will not use all of them ; since we want a working 

 knowledge of the following we will learn their use: 



The Substage, which is placed under the stage, is 

 to support the Abbe condenser. 



The Iris diaphragm is used to regulate the light 

 which passes through the condenser. 



The Abbe is a lens of a very short focal distance and 

 gives a very strong light. 



The Mechanical Stage is an instrument used to 

 manipulate the object while upon the stage. 



The Camera Lucida is an instrument used to assist 

 the student in making the drawings. 



The Polariscope is used to examine objects by means 

 of polarized light. 



The Micrometer is an instrument used to determine 

 the magnifying power of the microscope. There are 

 two kinds of micrometers, viz. : an eyepiece and a stage 

 micrometer. Determine the magnifying power of the 

 instrument at your desk. 



