CHAPTER I 

 APPARATUS 



The amount of apparatus required for histological work varies, 

 temporary mounts, glycerin mounts, and freehand sections requiring 

 only a razor and a microscope, while the paraffin method, which 

 represents the highest development of technic, brings into use nearly 

 all the equipment of the histological laboratory. The following 

 list includes only the apparatus necessary for making preparations: 

 a microscope; a microtome; a razor; a hone and a good razor strop; 

 a paraffin bath; a turntable; a scalpel; a pair of needles; a pair of 

 scissors; a pair of forceps; staining-dishes; solid watch glasses; 

 bottles; a graduate (50 or 100 c.c.); pipettes; slides, 1X3 inches; 

 round covers, 18 mm. or f inch in diameter; and square covers, f inch. 

 Longer covers will be needed for some of the serial sections. 



A microscope should have a rack and pinion coarse adjustment, 

 a fine adjustment, two eyepieces magnifying about four and eight 

 diameters, a low-power objective of about 16 mm. focus, and a 

 high-power objective of about 4 mm. focus, a double nosepiece, an 

 iris diaphragm, and an Abbe condenser. A cheap and practical 

 form is shown in Fig. 1, and similar instruments are for sale by all 

 the leading companies. 



Since the chemicals used in histological technic are likely to 

 damage the stage and substage of the microscope, it is well to place 

 upon the stage a piece of glass three or four inches square. A lantern- 

 slide cover is just right for this purpose. It is not necessary to 

 fasten it to the stage, since it is merely for protection while examin- 

 ing slides which are wet with reagents. In our own laboratory we 

 use for examining wet slides a cheap microscope with only a single 

 low-power objective and a single ocular. 



Some knowledge of the structure and optics of the microscope is 

 necessary if one is to use it effectively. Why are there so many 

 diaphragms ? Why is there an arrangement for raising and lowering 



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