Leishman stain

The methanolic stock solution is stable and also serves the purpose of directly fixing the smear eliminating a prefixing step.

[2] According to Sir John Vivian Dacie's textbook, Practical Haematology, "Amongst the Romanowsky stains now in use, Jenner's is the simplest and Giemsa's the most complex.

Whichever method is used, it is important to select dyes that are not contaminated with other dyes or metallic salts.Sir William Boog Leishman of London and Karl Reuter of Germany independently discovered in 1901 what is considered "Perhaps the most practical modifications of Malachowski’s stain"[4] They adopted the best aspects of the stains developed by Malachowski and Jenner, i.e., they used both polychromed methylene blue (accidentally done by Romanowsky who got the name, systematically done by Ernst Malachowski even before Romanowsky, and rediscovered by Bernhard Nocht, but unknown to Jenner, May, Grunwald and many others who used simple methylene blue) and filtering the Azure Eosinate precipitate from the aqueous mixture and redissolving in an alcoholic solvent (Jenner's wisdom).

Compared to the costly and toxic pure synthetic AZure B and Eosin Y based reagents used by the ICSH reference methods which are also not free from the disadvantage of getting oxidized and eventually giving grey tone instead of the optimal blue colors for cytoplasm, Leishman is a cheap easily available and easy to do technique which gives a fairly acceptable contrast.

It was only the work by Gustav Giemsa and the likes who again manually controlled the proportion of these two components that brought the depth of staining back.

However Giemsa and others who artificially controlled the proportion sometimes went to the other extreme (a large molar excess of Azure up to a ratio of 16.1) which was probably unnecessary.

Also its above counterparts it stains the nuclei dark purple and the nuclear feature details are not as clear as Hematoxylene and Eosin, which are thus preferred by some cytopathologists.