Tech. E:6 



r<APID PREPARATION OF TmPORAKY HEAD-MOUNTS 



The desirability of a rapid method using a viscous mounting medium 

 into which a specimen could be transferred directly from fixative or 

 water led to the use of methylcellulose. (Cairns and Tarjan 1955). 



Slides made by this method are of a temporary nature and are satis- 

 factory mainly for determining the surface structures and the internal 

 sclerotized parts of the nematodes' heads. These structures, unlike 

 the rest of the body, apparently are not distorted by this treatment 

 and are the anatomical elements usually considered of diagnostic value 

 in en face preparations. 



The viscous, clear mounting medium is prepared by heating 50 ml. of 

 distilled water in a beaker to about 80 to 90° C. Enough methyl- 

 cellulose of one of the higher viscosity types (e.g. UOO-U,000 cps.) 

 is immersed in the water so that it appears well soaked. After 30 

 minutes the mixture is cooled by partial immersion of the beaker in 

 cold water. If the material fails to dissolve completely, the beaker 

 is ininersed in ice water. If the material becomes too viscous during 

 or after its preparation, a small quantity of distilled water is added. 

 The material becomes slightly more fluid after a few days and bubbles 

 made by stirring disappear. 



The specimen is transferred into a drop of the medium on a glass slide, 

 its head is severed, and a cover-slip then placed directly on the 

 drop. Manipulation of the cover-slip will bring the nematode head into 

 the desired vertical position. The location of the head is indicated 

 in the usual manner by placing three dots on the cover-slip with India 

 ink in a triangular fashion aroiind the specimen. Application of molten 

 paraffin-petroleum jelly mixture to the edges of the cover-slip cements 

 it firmly in place so that shifting of the specimen will be greatly 

 reduced. The specimen is now ready for immediate examination. 



