7.3.
ALKALINE LEAD HYDROXIDE STAINS
229
first wash water then is poured off and the large bath refilled so that there
is a second dilution of the stain. Only then are the grids removed and
given a final wash with a jet of pure water before drying them.
We have had experience using this staining procedure with Millonig's
(1961) variant stain and it worked well. Presumably it would be a
satisfactory procedure with any of the other stain variants which are
described subsequently. Its use, though, is less necessary than with the
Watson stain for the variations which follow are not as prone to produce
contamination as the original Watson formulation. In this sense they are
intermediate in their properties between the Watson and the Reynolds
stains.
Millonig's
(1961) lead tartrate.
Millonig (1961) proposed adding tartrate as a "stabilizing agent" to alkaline lead hydroxide solutions. In
effect this apparently serves as a chelating agent rather like the citrate
that Reynolds (1963) subsequently used. Its protective action probably
should be explained in the same fundamental way. However, Millonig
did not advocate using tartrate in anything like the concentration in
which Reynolds employed citrate, so that in the former case the lead
surely is not as fully sequestered. Nonetheless the stain is an effective one
and is by no means as sensitive to contamination as the Watson formulation.
Two ways were suggested for making up the stain, employing different
lead salts as starting points. Method 1, employing commercially available
lead hydroxide, starts with a stock solution as follows:
In making up the staining solution, 0.5 ml of this is diluted to 100 ml
with distilled water, heated, and 1 gm of lead hydroxide (Amend Drug
and Chemical Co., Inc. New York) added. After cooling, this solution is
filtered and should remain clear and have a pH of about 12.3.
If lead hydroxide is not available, one can start with lead acetate
(Method 2). A similar stock solution, but containing more hydroxide, is
prepared as follows:
NaOH
K-Na-tartrate
H 2 0 to
12.5 gm
5.0 gm
50.0 ml
NaOH
K-Na-tartrate
H 2 0 to
20.0 gm
1.0 gm
50.0 ml
ALKALINE LEAD HYDROXIDE STAINS
229
first wash water then is poured off and the large bath refilled so that there
is a second dilution of the stain. Only then are the grids removed and
given a final wash with a jet of pure water before drying them.
We have had experience using this staining procedure with Millonig's
(1961) variant stain and it worked well. Presumably it would be a
satisfactory procedure with any of the other stain variants which are
described subsequently. Its use, though, is less necessary than with the
Watson stain for the variations which follow are not as prone to produce
contamination as the original Watson formulation. In this sense they are
intermediate in their properties between the Watson and the Reynolds
stains.
Millonig's
(1961) lead tartrate.
Millonig (1961) proposed adding tartrate as a "stabilizing agent" to alkaline lead hydroxide solutions. In
effect this apparently serves as a chelating agent rather like the citrate
that Reynolds (1963) subsequently used. Its protective action probably
should be explained in the same fundamental way. However, Millonig
did not advocate using tartrate in anything like the concentration in
which Reynolds employed citrate, so that in the former case the lead
surely is not as fully sequestered. Nonetheless the stain is an effective one
and is by no means as sensitive to contamination as the Watson formulation.
Two ways were suggested for making up the stain, employing different
lead salts as starting points. Method 1, employing commercially available
lead hydroxide, starts with a stock solution as follows:
In making up the staining solution, 0.5 ml of this is diluted to 100 ml
with distilled water, heated, and 1 gm of lead hydroxide (Amend Drug
and Chemical Co., Inc. New York) added. After cooling, this solution is
filtered and should remain clear and have a pH of about 12.3.
If lead hydroxide is not available, one can start with lead acetate
(Method 2). A similar stock solution, but containing more hydroxide, is
prepared as follows:
NaOH
K-Na-tartrate
H 2 0 to
12.5 gm
5.0 gm
50.0 ml
NaOH
K-Na-tartrate
H 2 0 to
20.0 gm
1.0 gm
50.0 ml