1.2.
EQUIPMENT
5
observe interference colors which are seen with suitably reflected light,
and which are a measure of section thickness.
A good photographic enlarger with a high quality, fast lens is an important investment. One should not try to save money on this item. A
number of modern electron microscopes offer a choice of plate size. The
enlarger lens and condenser system that works well with miniature
negatives will not also serve with large sizes or vice versa. Thus, if the
enlarger is to accommodate both small and large negatives, two different
lenses must be purchased as well as two different condenser systems.
Enlargers which rely on diffusing systems rather than condenser lenses
should be avoided for they do not produce maximum contrast. Also a
fluorescent light source does not yield maximum contrast.
An electric print dryer is necessary to handle the volume of prints that
may be expected. A good analytical balance, pH meter, laboratory oven,
and refrigerator, and probably also a small centrifuge, must also be put
on the essential list.
As far as desirable equipment goes, at least one further binocular
dissecting microscope is very useful, particularly if three or more people
are working in the laboratory more or less simultaneously. There are
endless minor tasks which are best performed with its aid: trimming
specimens, trimming blocks, examining apertures and polepieces for
contamination, surveying specimen screens, picking up sections on
screens, examining negative detail, as well, perhaps, as delicate operations
on small animals. If there is only one general purpose instrument available, this can become an annoying and inefficient bottleneck.
An ordinary compound microscope is occasionally important, particularly for studying and measuring apertures, although much of the
time it may stand idle. Certain types of work, however, require a close
correlation between ordinary light microscopy and electron microscopy,
and then such an instrument may be used regularly. A phase contrast
microscope is also desirable, for with it one can check on the contents
of ultrathin sections as they are being cut by taking a sample section
0.5-1 \i thick, and looking at it directly after covering it with immersion
oil (Chapter 7.13).
In the darkroom a photoelectric densitometer for judging the exposure
for enlarging is useful.
A small electronic "shop" is almost essential. Even the complete novice
will, on occasion, have to wield a soldering iron, and he should soon
learn to use a volt-ohmmeter. If he is or becomes more knowledgeable,
EQUIPMENT
5
observe interference colors which are seen with suitably reflected light,
and which are a measure of section thickness.
A good photographic enlarger with a high quality, fast lens is an important investment. One should not try to save money on this item. A
number of modern electron microscopes offer a choice of plate size. The
enlarger lens and condenser system that works well with miniature
negatives will not also serve with large sizes or vice versa. Thus, if the
enlarger is to accommodate both small and large negatives, two different
lenses must be purchased as well as two different condenser systems.
Enlargers which rely on diffusing systems rather than condenser lenses
should be avoided for they do not produce maximum contrast. Also a
fluorescent light source does not yield maximum contrast.
An electric print dryer is necessary to handle the volume of prints that
may be expected. A good analytical balance, pH meter, laboratory oven,
and refrigerator, and probably also a small centrifuge, must also be put
on the essential list.
As far as desirable equipment goes, at least one further binocular
dissecting microscope is very useful, particularly if three or more people
are working in the laboratory more or less simultaneously. There are
endless minor tasks which are best performed with its aid: trimming
specimens, trimming blocks, examining apertures and polepieces for
contamination, surveying specimen screens, picking up sections on
screens, examining negative detail, as well, perhaps, as delicate operations
on small animals. If there is only one general purpose instrument available, this can become an annoying and inefficient bottleneck.
An ordinary compound microscope is occasionally important, particularly for studying and measuring apertures, although much of the
time it may stand idle. Certain types of work, however, require a close
correlation between ordinary light microscopy and electron microscopy,
and then such an instrument may be used regularly. A phase contrast
microscope is also desirable, for with it one can check on the contents
of ultrathin sections as they are being cut by taking a sample section
0.5-1 \i thick, and looking at it directly after covering it with immersion
oil (Chapter 7.13).
In the darkroom a photoelectric densitometer for judging the exposure
for enlarging is useful.
A small electronic "shop" is almost essential. Even the complete novice
will, on occasion, have to wield a soldering iron, and he should soon
learn to use a volt-ohmmeter. If he is or becomes more knowledgeable,