(Not included in copyright.) Tech. E:7 



PEHMANENT MOUNTS IN GLYCEKDJE (THOWJE'S METHOD) 



1. Heat specimens in water in a depression slide very gently until 

 they are killed. Frequent checking under the dissecting microscope 

 is required if heating is done over a small flame or on a slide 

 warming table. A better method is to put the specimens in a small 

 amount of water in a "B.P.I." watch-glass and place in an incuba- 

 tor at 110° F. for about 20 minutes or at 120° F. for about 5 

 minutes. 



2. Drain off the water with a fine pipette, add formalin-aceto-alcohol 

 fixative. After a few minutes, draw off the liquid and add fresh 

 fixative. Leave for 2U to I48 hours, the longer time is preferred. 



3. Transfer the nematodes to a solution of l\% glycerine in 30^ ethyl 

 alcohol contained in a "B.P.I." watch-glass. 



U. Place the watch-glass in a small desiccator. The desiccant is kept 

 in a small, screw-capped vial with a hole of about one millimeter 

 in diameter bored in the cap. Two grams of desiccated calcium car- 

 bonate is the amount of desiccating agent used. Calcium chloride 

 is not used, because its use in this manner results in too rapid 

 uptake of the moisture in the small desiccator. Allow three weeks 

 for dehydration of the alcohol-glycerine solution; complete dehy- 

 dration in less time is not desired. 



5. After the water has thus been removed, after the three or more weeks 

 required, transfer the watch-glass with the nematodes to a large 

 calcium chloride desiccator for three days. Transfer specimens to 

 pure glycerine, the supply of which is kept in a calcium chloride 

 desiccator. 



6. Mouni. specimens in a drop of piire desiccated glycerine on a slide 

 clearied with acidulated alcohol. Aid glass-wool supports wMch 

 have been kept in dehydrated glycerine. Orient supports and speci- 

 mens and add a clean cover-glass that vras preheated slightly. The 

 cover-glasses used are selected for freedom from defects, #00 in 

 thickness, and cleaned in acidulated alcohol. 



7. Seal the cover-glass with ZUT and label slides. 



The advantage of using the special metal slides, by means of which 

 nematodes can be mounted between two cover-glasses for observation 

 of both sides, will be appreciated for permanent slides of scarce 

 specimens needed for taxonomic purposes. 



