For years I have used in my laboratory a method for the staining of blood-films which has proved so satisfactory from all points of view as to have earned the term "invariable." The idea is not original with me, but is based on two well-known principles, combined, modified and finally perfected. First of all, single films are best fixed by burning in absolute alcohol; a proper mixing of eosin with Ehrlich's acid hematoxylin gives an excellent stain, one which proved its worth before the panoptic formulas became so popular.
This method is especially suited to the needs of the general practitioner, the man who desires invariable results and who cannot become proficient in technic. Certain men, who do considerable blood work, are now using the "invariable" almost routinely. Several of these have prevailed on me to publish the formula and technic; and this will perhaps justify the addition of another