2010 Journal of Applied Microscopy 



Mtiir (1891) made the Ehrlich films and placed them at once, before any 

 drying occurred, on the surface of a saturated solution of corrosive sublimate to 

 which was added \ per cent, of sodic chloride,— preferably heated to a tempera- 

 ture of 50° C. — where they were allowed to remain for about half an hour. 

 The preparations were then thoroughly washed in \ per cent, common salt solu- 

 tion, taken through successive strengths of alcohol and then stained. It is rec- 

 ommended that salt in the same proportion be added to the weaker strengths of 

 alcohol. 



Romer (1892) placed the fresh blood films directly into a saturated watery 

 solution of sublimate for six minutes, then into distilled water for two minutes, 

 absolute alcohol one minute, distilled water one minute, followed by the staining 

 solution — in this case haematoxylin followed by eosin. 



8. Osmic Acid.— Afanassiew (1884), Hayem (1890), Laveran (1891), Luzet 

 (1891), and Heiman (189s) exposed the undried blood films to the vapor of 

 osmic acid. Heiman used 1 per cent, solution. Laveran mixed a drop of blood 

 with a drop of a solution of osmic acid 1 in 300 on a slide, applied a cover-glass, 

 and permitted the stain (glycerin in which picro-carmin is dissolved) to flow 

 through. This method was used for malarial blood. 



Deetjen (1901) used the vapors of osmic acid or one per cent, osmic acid to 

 fix blood plates in fresh blood in which the cells were kept from dying by being 

 spread on his agar solution (IV, 9). 



9. Osmic Acid and Acetic Acid.^Dekhuyzen (1901) used 8-1 or 9-1 osmic 

 acid (3 or 9 volumes of 2 per cent, osmic acid with one volume of 6 per cent, 

 acetic acid, containing \ per cent, methylen blue) for fixing blood plates. With 

 invertebrates the acetic acid sometimes produces an objectionable precipitate of 

 granular albumen, then osmic acid was used alone. 



10. Picric Acid. — Freeborn (18S9) gives Gage's method for amphibians' 

 blood : "Three or four drops of fresh blood are allowed to fall into 10 c. c. of 

 normal salt solution, contained in a tall glass cylinder. Agitate thoroughly, and 

 mix with 100 c. c. of a saturated aqueous solution of picric acid with constant 

 stirring. Allow the blood cells to settle, and pour off as much of the superna- 

 tant fluid as possible, add an equal amount of normal salt solution; continue 

 this until the salt solution is only slightly tinged yellow. Then add 10 c. c. of 

 a mixture of 5 parts of carmin and 95 parts of picro-carmin for staining. This 

 requires about 15 hours. Then pour off as much of the staining fluid as possible 

 and add 10 c. c. of acid glycerine (glycerine 100 c. c, hydric or formic acid 1 c. c). 

 The cells may be kept in this mixture indefinitely. For mounting, remove a 

 drop with a pipette, place it on a slide, cover, and cement the cover imme- 

 diately. Ernest L. Walker. 

 Massachusetts State Board of Health. 



