A NEW AND STABLE SOLUTION OF GENTIAN VIOLET FOR THE GRAM STAIN

Unfortunately for the simplification of an often complex problem, we now know that bacteria cannot be divided, as was once thought, into two great classes of Gram-positive and Gram-negative. It is true that many of the varying and contradictory statements on this head may be explained on the score of variations in technic, such as the length of time the stain and the alcohol were allowed to act, and the age of the culture experimented with; but it is nevertheless a fact that organisms repeatedly and consistently found to be Gram-negative will sometimes take the stain very well.

Thus, Zimmermann¹ found that all cultures of the Bacterium fluorescens stain well in young cultures; and Lehmann and Neumann² found that three out of twelve cultures of the same organism stained beautifully, yet this is a species spoken of in the literature as Gram-negative. The latter workers also stained the bacillus of