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 hable 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 shde carefully over a spirit 

 lamp or gas flame, being sure not to 

 melt thtf 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). 



Fig. 229. Kingsbury's Electeic Spread- jf q^q jg jn haste to take 

 iNG PLATE ANB In^h-traxing Box. ^^^ g^eceeding steps in the 

 The top projects and any temperature is iv i-j u 



obtainable. If need be the projecting end preparation, the shde may be 

 can be heated with a Bunsen burner or an dried by putting it into a dry- 

 alcohol lamp. The wiring is as shown in . „<- qo +„ ,„o /-■ f^y 

 Fig. 220. iiig °v^^ ^t 38 to 40 C. for 



Fig. 228. Electric Spreading 

 Plate and Ineiltrating Box. 



(From the Anatomical Record). 



A The upper part of the box 

 on which is lie spreading plate. 



B Base, or tray in which the 

 infiltrating dishes are placed (see 

 Fig. 220). 



S A sUde 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. 



