PREPARATION 19 



Hardening. — When the washing is completed, the specimens 

 should be transferred to 95 per cent alcohol. If the specimens 

 are hardened by remaining in this solution for about twenty 

 minutes, thej^ particularly the soft baggy ones, will be greatly 

 benefited. This step can be omitted if desired. 



Staining.— If the specimens are to be stained, the general rule 

 is that they should be transferred from the hardening solution to 

 the stain if an alcoholic stain is used and to water and then to 

 the stain if an aqueous stain is used. This will be found unneces- 

 sary if the stain recommended on a following page is used as 

 specimens can be placed in the stain from either water or alcohol. 

 While it takes more time to stain specimens, the greater ease with 

 which they can be studied and the much greater visability of many 

 characters that are just or not at all perceptible in unstained 

 specimens, more than repays for the extra time required. 



Many solutions have been suggested, as safrannin, gentian 

 violet, picric acid, picro-creosote, Delafield's haematoxylin, 

 fuchsin, saurefuchsin, and carbolic fuchsin. Some writers have 

 confused fuchsin and saurefuchsin and their various commercial 

 names. Fuchsin is a basic stain containing rosanilin, and is 

 variously known as fuchsin, analin red, rubin, rosein, magenta, 

 etc. Saurefuchsin is an acid stain containing rosanilin and known 

 as acid fuchsin, fuchsin S, acid rubin, saurerubin, acid magenta, 

 and saurefuchsin. Gage, who experimented extensively with these 

 various stains and most of the others named, concluded that the 

 best results were obtained by the use of an aqueous solution of 

 saurefuchsin. As he pointed out, one of the great difficulties with 

 stained specimens of coccids is that they may be sharply stained 

 and well differentiated when mounted, but in the course of a few 

 weeks or months they have lost all trace of the stain. The fading 

 of saurefuchsin was shown to be due to the presence of caustic 

 potash in the specimens. The washing of the specimens needs, 

 therefore, to be done with great care and thoroughness and, if there 

 is any question as to the complete removal of the caustic potash, 

 the specimen should be washed in acidulated water or alcohol, 

 1 cc. hydrochloric acid to 99 cc. distilled water. 



The staining should be done while the specimens are in vials 

 or watch-glasses. It will require from ten to forty minutes, 

 depending upon the size of the specimens and the condition of their 

 cuticle. If the specimens are overstained, the excess stain can be 

 removed with a dilute solution of caustic potash, one-half per cent 



