CUTTING flND MOUNTING TISSUES. 



The methods of cutting and mounting tissues are indeed 

 numerous and only the more important ones will be reviewed. 



Free-Hand Sectioning. 



Many things can be prepared for study in this way. The tis- 

 sue must be firm in order that it may not be crushed under the 

 knife and yet not be too hard or brittle to prevent its cutting readily. 

 The object to be sectioned should be held between the thumb 

 and fore finger, while the razor should rest on the tip of the finger 

 with the edge inward. Draw the knife, with the edge pressing 

 against the tissue, across the finger keeping the thumb well below 

 the line of cutting. Do not try to cut large sections but make 

 them small and if need be wedge-shaped in order to get a 

 piece thin enough for study. It is usually best to keep the tissue 

 wet with alcohol or water to make the sectioning easy. Transfer 

 the sections from the razor to the slide with a camel's hair brush . 



If the object to be sectioned is quite small it can be placed 

 between two pieces of elder pith or cork and sections made through 

 these which shall include in them the sections of tissue. It is 

 often very convenient to fasten the tissue with the cork, or if large 

 enough, directly in a microtome, and section with a microtome 

 knife or razor, keeping the object and knife wet as before directed. 



This method is a very useful one for the transections of woody 

 stems and firm tissues. These can frequently be softened without 

 shrinking by leaving them for some time in glycerin, and in the 

 case of the firmest ones, boiling for five minutes or more. Many 

 small objects can be held for sectioning by placing them at once in 



