11. Particulate Specimens,
Negative Staining
11.1. Introductory Remarks
In the past few years "negative staining" has proved to be a most
valuable and important technique for the examination of fine surface
detail of suitably small particulate specimens. Basically the method
consists of embedding the particles in question in a layer of dense
material so that the specimen is viewed as a relatively light object against
a dark background. Of course the term which has come to be applied to
the technique is completely misleading, for staining in the proper sense
of the word is not involved at all, and the only "negative" feature is the
dark-field effect of a light object against a dark background. However,
the unfortunate term is already so ingrained in the literature that there
is no likelihood of substituting a more appropriate expression.
Negative staining first was used deliberately by C. Hall as long ago as
1955 although, indeed, Farrant had observed the effect previously (1954).
Next, Huxley (1956) described negatively stained tobacco mosaic virus
particles. Subsequently he indicated that this was an independent rediscovery of the technique (Huxley and Zubay, 1960). Presumably it was
Huxley's influence that stimulated a group of English virologists to extraordinarily fruitful applications in their fields. They did much to develop the technique as we now know it (Brenner and Home, 1959; Home
and Brenner, 1960; Valentine, 1959, 1960). Dutch, Italian, German, and
American investigators also participated in the exciting developments of
this period as the reports presented at the European Conference on Electron Microscopy held in Delft in 1960 demonstrated. Valentine and
Home (1962) summarized much of the useful knowledge that has developed since concerning the technique.
11.2. Theoretical Aspects of Negative Staining
As indicated above, negative staining involves embedding suitably
small particulate matter in a layer of dense material so that the specimen
is viewed as a light object against a dark background. Successful and
346
Negative Staining
11.1. Introductory Remarks
In the past few years "negative staining" has proved to be a most
valuable and important technique for the examination of fine surface
detail of suitably small particulate specimens. Basically the method
consists of embedding the particles in question in a layer of dense
material so that the specimen is viewed as a relatively light object against
a dark background. Of course the term which has come to be applied to
the technique is completely misleading, for staining in the proper sense
of the word is not involved at all, and the only "negative" feature is the
dark-field effect of a light object against a dark background. However,
the unfortunate term is already so ingrained in the literature that there
is no likelihood of substituting a more appropriate expression.
Negative staining first was used deliberately by C. Hall as long ago as
1955 although, indeed, Farrant had observed the effect previously (1954).
Next, Huxley (1956) described negatively stained tobacco mosaic virus
particles. Subsequently he indicated that this was an independent rediscovery of the technique (Huxley and Zubay, 1960). Presumably it was
Huxley's influence that stimulated a group of English virologists to extraordinarily fruitful applications in their fields. They did much to develop the technique as we now know it (Brenner and Home, 1959; Home
and Brenner, 1960; Valentine, 1959, 1960). Dutch, Italian, German, and
American investigators also participated in the exciting developments of
this period as the reports presented at the European Conference on Electron Microscopy held in Delft in 1960 demonstrated. Valentine and
Home (1962) summarized much of the useful knowledge that has developed since concerning the technique.
11.2. Theoretical Aspects of Negative Staining
As indicated above, negative staining involves embedding suitably
small particulate matter in a layer of dense material so that the specimen
is viewed as a light object against a dark background. Successful and
346