Tech. A: 2 



mounted specimen. Equipment for making these slides is available 

 on loan from various laboratories. Contact one of the authors 

 for more information. 



2, Covfar-gLasses of best quality are to be preferred. They should be 

 of #0 thickness for routine work. Circles of 3/U inch diameter 

 are generally used. Square cover-slips may be satisfactory and 

 are less expensive, 



3. Slide sealing materials are of various kinds. An ideal sealing 

 cement ZUT was devised by G, Thome (1935) and is widely used by 

 phytonematologists. It is used to seal water, formalin, T A F, 

 lactophenol, and glycerine m.ounts. It dries quickly and resists 

 action of solvents used for removing immersion oil from the 

 cover-slips. ZUT is obtainable in pint and quart amounts from; 

 Bennett's, 65 'iest First South Street, Salt Lake City 10, Utah. 

 The recommended thinner for ZUT is butyl acetate. Ethyl acetate 

 has been found to be a satisfactory suiDstitute, and acetone may 

 also be used, but the latter may produce small bubbles in the 

 applied ZUT seal. 



Lactophenol gum is a cement used to seal lactophenol mounts. The 

 directions for its preparation (Davis, 192ii) are as follows: 

 Dissolve 38 grams of pure gum arable in 50 ml, of distilled water, 

 add 5 grams of glucose and 6 grams of lactophenol. The solution 

 is then filtered through glass-wool. Lactophenol consists of a 

 solution made by mixing 3 parts melted phenol, 1 part lactic acid, 

 2 parts glycerine, and 1 part water. 



Other slide sealing cements include: Cleared , used to seal 

 lactophenol mounts, obtainable from H. W. Clark, 5Ul9 - 32nd 

 Street, N. W., Washington, D. C; par af fin- vaseline mixtiire) 

 50-50, for temporary water and formalin mounts; gold-size varnish 

 and bakelite resin varnish and other materials can be used, pro- 

 vided that they are not effected by the mounting medium or by the 

 solvents used to remove immersion oil. 



A slide-ringing turntable is not necessary. When used for making 

 neat seals of round cover-glasses, extra precaution should be 

 taken to provide a seal of sufficient thickness, particularly 

 if the ringing compound is thinned for easier application. Seals 

 applied freehand are likely to be thicker, and round as well as 

 square cover-glasses can be safely sealed in this manner, even 

 if somewhat less neatly. Sources of turntables are the Will 

 Corp., Ho Chester 3, N. Y.j and the Southern Scientific Co., Inc., 

 Atlanta 3, Georgia. 



U. Cover-glass supports are necessary to prevent distortion of the 

 nematode specimens by the pressure of the cover-glass, liJhatever 

 the kind of support used, it is imperative that it be only 

 slightly thicker than the cross-sectional diameter of the nematodes. 



