TECHNIC 



505 



bed so that the sections should always be cut from one surface or side of the 

 box, preferably the under surface. Cut sections, on a rotary microtome, 5 to 10 

 microns thick. Attach to a clean slide by placing several drops of water on the 

 slide and floating the sections on, taking care to remove all air bubbles caught under 

 the folds of the sections. Heat on the top of water bath to a point not over 15 

 to 10 below the melting point of the paraffin used. If the section melts at any point, 

 such part will not afterwards adhere. When the section has straightened out under 

 this gentle heat, allow the water to drain from under it and arrange it to suit with a 

 needle or scalpel; never work with one tool, but have one pointed instrument in each 

 hand so that if the section sticks to one instrument the other can be used to release it. 

 Surface tension will make or mar the arrangement according as it is understood and 

 used, or ignored and fought with. Thus two rows of flattened sections, freely floating, 

 may absolutely refuse to be drawn together to make room for a third row outside of 

 them. If now the point of a scalpel be drawn between them several times to break up 

 the invisible film of paraffin on the water, they will come together themselves. In fact, 

 they could not be kept apart. 



When arranged, place the slides in a dry, well-ventilated place for six or more 

 hours to dry out completely. The sections will then adhere through any other pro- 

 cess. When the fixative contains chromic acid or any of its compounds, egg fixative 

 must be very slightly smeared on the slide before placing the water and sections 



