230
7.
"STAINING"
In making up the stain, 1 ml of this solution is added to 5 ml of a 20%
lead acetate solution, which is then stirred and diluted 5-10 times with
distilled water. Finally it is filtered, and the resulting solution should
also be colorless and clear, and can be assumed to contain the same
staining salt as that prepared with lead hydroxide. Either of the stains
can be stored for long periods of time.
Karnovsky's
(1961) lead hydroxide.
Karnovsky (1961) came to believe
that the stability of lead hydroxide solutions was improved by great
alkalinity, and his formulations have a pH of about 12. He presented
two variant methods. In his "Method A," 15-20 ml of sodium hydroxide
are placed in an Erlenmeyer flask and lead monoxide added to excess.
The mixture is gently boiled for 15 minutes. Then the flask is cooled
rapidly, and the solution filtered. This is a stock solution which can be
kept in a closed container for months. Stains are prepared by diluting this
50-200 times with distilled water. The diluted stains also have good
stability.
Karnovsky's "Method B" adds lead monoxide in excess to 10-15 ml of
10% sodium cacodylate in water, and the mixture again is boiled for
15 minutes. After rapid cooling the mixture is filtered and is a stable
stock solution. Stain is prepared by a 5-fold dilution of a small quantity
of stock solution with 10% sodium cacodylate with stirring. Then 1 N
sodium hydroxide is added drop by drop with thorough stirring between
each addition. A faint cloudiness will form, but when enough sodium
hydroxide has been added the solution will clear once more. It is important not to over-titrate. The clear solution is the stain and it can be
kept for several months if kept stoppered.
Karnovsky supposed that the effective staining agent was the plumbite
anion. Thus his interpretation of the significant radical, and the mechanism of staining, differs from that of Reynolds (1963) who believes that
cationic radicals are the effective components of alkaline lead stains.
Lever's (1960) lead hydroxide.
Lever (1960) proposed an effective stain
which he believed to be potassium plumbite, and which seemed to be less
prone to contamination than Watson's original formulation. This was
made very simply by adding 100 ml of distilled water to 1 gm of lead
hydroxide, and bringing this to a boil. The suspension then was cooled
slightly and filtered. To the filtrate, which was faintly clouded, was added
a solution of 2 AT KOH, drop by drop, until on agitation a completely
clear solution remained. This was the staining fluid.
Dalton
and ZeigeVs (1960) lead staining
method. Dalton and Zeigel
7.
"STAINING"
In making up the stain, 1 ml of this solution is added to 5 ml of a 20%
lead acetate solution, which is then stirred and diluted 5-10 times with
distilled water. Finally it is filtered, and the resulting solution should
also be colorless and clear, and can be assumed to contain the same
staining salt as that prepared with lead hydroxide. Either of the stains
can be stored for long periods of time.
Karnovsky's
(1961) lead hydroxide.
Karnovsky (1961) came to believe
that the stability of lead hydroxide solutions was improved by great
alkalinity, and his formulations have a pH of about 12. He presented
two variant methods. In his "Method A," 15-20 ml of sodium hydroxide
are placed in an Erlenmeyer flask and lead monoxide added to excess.
The mixture is gently boiled for 15 minutes. Then the flask is cooled
rapidly, and the solution filtered. This is a stock solution which can be
kept in a closed container for months. Stains are prepared by diluting this
50-200 times with distilled water. The diluted stains also have good
stability.
Karnovsky's "Method B" adds lead monoxide in excess to 10-15 ml of
10% sodium cacodylate in water, and the mixture again is boiled for
15 minutes. After rapid cooling the mixture is filtered and is a stable
stock solution. Stain is prepared by a 5-fold dilution of a small quantity
of stock solution with 10% sodium cacodylate with stirring. Then 1 N
sodium hydroxide is added drop by drop with thorough stirring between
each addition. A faint cloudiness will form, but when enough sodium
hydroxide has been added the solution will clear once more. It is important not to over-titrate. The clear solution is the stain and it can be
kept for several months if kept stoppered.
Karnovsky supposed that the effective staining agent was the plumbite
anion. Thus his interpretation of the significant radical, and the mechanism of staining, differs from that of Reynolds (1963) who believes that
cationic radicals are the effective components of alkaline lead stains.
Lever's (1960) lead hydroxide.
Lever (1960) proposed an effective stain
which he believed to be potassium plumbite, and which seemed to be less
prone to contamination than Watson's original formulation. This was
made very simply by adding 100 ml of distilled water to 1 gm of lead
hydroxide, and bringing this to a boil. The suspension then was cooled
slightly and filtered. To the filtrate, which was faintly clouded, was added
a solution of 2 AT KOH, drop by drop, until on agitation a completely
clear solution remained. This was the staining fluid.
Dalton
and ZeigeVs (1960) lead staining
method. Dalton and Zeigel