Ch. XI] PREPARATIONS BY THE PARAFFIN METHOD 



383 



formed, viz. : the sections are made smooth and they are also fastened 



to the slide. Put a minute drop of albumen fixative on the middle 



of a slide and with the ball of one 



finger spread it over the slide, making 



a thin even layer. It cannot be too 



thin. It is liable to stain if it is too 



thick. 

 With a pipette (fig. 234) put several 



drops of water on the slide and then 



place a piece of ribbon on the water; 



or put the sections on the albumenized 



slide and add the water afterward. 



Heat the slide carefully over a spirit 



lamp or gas flame, being sure not to 



melt the paraffin. As the water warms 



the paraffin expands and stretches the 



sections out smooth. A copper heating 



plate is good for spreading sections; 



but the electric spreaders are best (fig. 



226-230). 



§ 620. Drying the sections. — After 



the sections are spread, drain off most 



of the water, arrange the sections with a needle or scalpel, and place 



the slide in one of the trays 

 (fig. 206-207). Allow it to 

 remain overnight or prefer- 

 ably longer. The longer the 

 drying in air the more surely 

 do the sections adhere to the 

 glass slide; or use the drying 

 oven (fig. 244). 



If one is in haste to take 

 the succeeding steps in the 

 preparation, the slide may be 

 dried by putting it into a dry- 

 ing oven at 38 to 40 C. for 



Fig. 228. Electric Spreading 

 Plate and Infiltrating Box. 



(From the Anatomical Record). 



A The upper part of the box 

 on which is the spreading plate. 



B Base, or tray in which the 

 infiltrating dishes are placed (see 

 Fig. 220). 



S A slide with sections being 

 spread. 



a, b The lamp socket and 

 separable plug and the supply 

 cable. 



i Insulation where the cable 

 passes into the box. 



Fig. 229. Kingsbury's Electric Spread- 

 ing Plate and Infiltrating Box. 



The top projects and any temperature is 

 obtainable. If need be the projecting end 

 can be heated with a Bunsen burner or an 

 alcohol lamp. The wiring is as shown in 

 Fig. 220. 



