The report of one or several "new" stains for diphtheria bacilli almost every year since 1895 would seem to indicate that none of those previously recommended have been entirely satisfactory.
I have tried practically every stain heretofore described. A rather critical review of these will appear before long in the American Journal of Public Health.
My purpose here is to make available the formula for a new method of staining diphtheria bacilli which I have developed and which my associates and I have found to be more satisfactory than any stain heretofore described. Two solutions are used:
Solution 2 is the same as the iodin solution used in the Gram stain:
TECHNIC OF STAINING
Smears are made on slides or cover glasses in the usual manner, fixed by heat, and stained with toluidin blue solution for five minutes. The stain is then drained off without washing, and the iodin solution
Albert H. A NEW STAIN FOR DIPHTHERIA BACILLI. JAMA. 1920;74(1):28. doi:10.1001/jama.1920.26210010001011