58 Animal Microloyy 



cover bore moisture. Passing a cover-glass quickly through a flame 

 before putting it onto the object will remove moisture, (d) The acid has 

 not been entirely removed from the sections, (e) Too much albumen 

 fixative has been used. (/) The glycerin of the albumen fixative has not 

 been removed by passing sections of objects stained in bulk 

 (see vi, 4) back into absolute alcohol after removing paraffin 

 from them. 



The defect may be remedied frequently by dissolving off 

 the cover in xylol or turpentine, descending through the 

 series of reagents to the point where the fault lies, correcting 

 and ascending again according to the regular method. To 

 remove water, for example, it is only necessary to go back 



as far as absolute alcohol which has a great affinity for water. 

 FIG. 31. 

 Dropping- 16. Dry or Dull-Looking Areas under the Cover-Glass indicate 



that the sections were allowed to get dry after the removal 

 from the clearer, or that insufficient balsam was applied. 



17. Balsam Which Exudes from under the Cover may be scraped off with 

 an old knife after it hardens. Remove the last traces by means of a 

 brush or a cloth dipped in turpentine or xylol. Balsam may be removed 

 from the surface of a cover by means of a brush dipped in xylol. 



18. If Sections Wash off the Slide the defect is probably due to one 

 of the following causes: (a) The slide was soiled or oily. Remedy by 

 cleaning slides thoroughly (see M). (6) The albumen fixative is too old. 

 (e) The transitions in the alcohol have been too great. This is true some- 

 times of thick sections. 



19. Flooding Sections with the Dye by means of a pipette, especially 

 in case of stains which act rapidly (e. g., eosin, acid fuchsin, Lyons 

 blue, picric acid, etc.), is sometimes more convenient than immersing 

 the sections in a jar of the staining fluid. Small bottles with com- 

 bination rubber stopper and pipette (Fig. 31) are now provided for this 

 purpose by dealers. 



20. Balsam Mounts in Which the Stain Has Faded may frequently be 

 restained, either with the original or with other stains. All that is 

 necessary is to dissolve off the cover in xylol (2 to 3 days) and pass the 

 preparation down through the alcohols to the stain in the usual manner. 



21. Ink for Writing on Glass (Hubbert, Journal of Applied Micros- 

 copy, Vol. V, p. 1680). Mix drop by drop 3 parts of a 13 per cent, alco- 

 holic solution of shellac with 5 parts of a 13 per cent, aqueous solution of 

 borax. If a precipitate forms, heat the solution until it clears. Add 

 enough methylen blue to color the mass deep blue. 



