Lactic-acetic-orcein stain

Stain slides with 2% lactic-acetic-orcein by adding a drop of stain to the slide and then placing a cover glass onto it. After some 2 min, gently press the cover glass and the slide within a bibulous pad to remove excess of fluid. Slides prepared this way do not dry up for at least a month. 

Staining may be achieved by acetic-orcein, lactic-acetic-orcein, or 2% toluidine blue. 

Small pieces of tubules (1-2 cm length) are placed on a slide and stained with a drop of lactic-acetic-orcein. 

The preparations can be stored or stained immediately with lactic-acetic-orcein, toluidine, or Unna blue. Toluidine blue is generally preferred for immediate examination of nonpermanent preparations. Lactic-acetic-orcein and Unna blue are used for finer examination and for permanent preparations. 

Dissolve 2 g of orcein (natural) in 45 ml of hot glacial acetic acid. When the solution is cooled, add 7.5 ml of distilled water and 47.5 ml of lactic acid. Filter and store (4°C) in a brown bottle. Filter the stain periodically. Long storage will result in precipitation of the stain. 

Staining Solution of Lactic Acid, Acetic Acid, and Orcein... 

Place a drop ( 25 ll) of staining solution containing lactic acid, acetic acid, and orcein on a siliconized coverslip. After the glands are fixed sufficiently, transfer them to the drop of staining solution. Allow the glands to sit in the staining solution for several minutes. 

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