Please read carefully this link (Dako Cy) and you can see the difference between

hematoxylin (see formula in the link) and protargol.

http://www.dako.com/08066_guide_to_special_stains.pdf

I join a copy of protargol and Hematoxylin/Eosin :

The Staining for Silver Pigmentation for

Visualization of OLCS

We used a modified staining protocol based on Bodian’s

protargol-S procedure. The dewaxed sections were

soaked in a 1% Protargol-S solution, diluted in borax-boric

acid (pH 7.4; Merck KGaA, Darmstadt, Germany) for

30 hr at 37C. After rinsing with distilled water, the

reaction was enhanced by an aqueous solution containing

0.2% hydroquinone (Wako Pure Chemical Industries,

Osaka, Japan), 0.2% citric acid (Wako), and 0.7% nitric

silver (Wako). After an additional rinsing, the sections

were reduced for 5 min with an aqueous solution of 2.5%

anhydrous sodium sulfate (Junsei Chemical, Tokyo, Japan),

0.5% potassium bromide (Wako), and 0.5% amidol

diaminophenol dihydrochloride (Wako). They were then

treated with 1% gold chloride (Wako) and subsequently

reduced by 2% oxalic acid amidol (Wako) until blackstained

osteocytic canaliculi could be seen. After rinsing

with distilled water, the sections were fixed in 5% sodium

thiosulfate (Wako) and stained with H–E.

JRG

Try to find publications authored by W.FOISSNER (Salzburg, Austria), e.g. b googleing:

< foissner wilhelm salzburg >  and/or 

If you then can find a publication list of this renowned you'll certainly find out what the best method for staining ciliates will be ((Foissner 1983, 1991, protocol A, 1992, etc.etc.

Best of luck, W.M.