146
5.
SECTIONING
one cannot cut slowly while cycling rapidly. Information available to me
does not indicate actual cutting speeds, but my impression is that the
minimum speed would be substantially more than 2 mm/sec. The microtome can be hand-operated, in which case slow cutting speeds could be
obtained, coupled with fast cycling. However, since the microtome has a
thermal drive, section uniformity would depend upon maintaining a
rhythmical cycle. I have not had experience with this microtome beyond
seeing it demonstrated.
5.9. JUM-5 Ultramicrotome
This instrument is a product of the Japan Electron Optics Laboratory
Co. Ltd., Tokyo, which also maintains a permanent outlet in Paris. I
have very little information about this microtome beyond what is available in an advertising brochure. The microtome has a thermal expansion
drive, and the block traverses an almost circular path so that it bypasses
the knife on the upstroke, rather like the Porter-Blum microtome. I do
not have information on how this is controlled or the nature of the
bearings in this instrument. A simple, variable speed motor drive cycles
the instrument. No provision is made for rapid cycling coupled with
slow cutting speed. I have no information on minimum cutting speed
beyond the comments of an investigator who had used the instrument
and suggested that it might be comparable to a Porter-Blum microtome
operated in such a way as to give about 5 mm/sec. I do not know of this
instrument ever even being demonstrated in the United States, although
advertising brochures have been available through the Fisher Scientific
Company, Boston, Massachusetts, who are American agents for the JEM
electron microscopes manufactured by the same company.
5.10. Sorvall MT-2 Ultramicrotome
The newest fully automatic microtome is a product of Ivan Sorvall
Inc., Norwalk, Connecticut. It is an elaborate derivative of their original
Porter-Blum microtome, and continues to carry this name. Although its
introductory price is competitive with other automatic microtomes, it is
by far the most complex instrument mechanically, and it may not prove
possible to maintain this relationship.
5.
SECTIONING
one cannot cut slowly while cycling rapidly. Information available to me
does not indicate actual cutting speeds, but my impression is that the
minimum speed would be substantially more than 2 mm/sec. The microtome can be hand-operated, in which case slow cutting speeds could be
obtained, coupled with fast cycling. However, since the microtome has a
thermal drive, section uniformity would depend upon maintaining a
rhythmical cycle. I have not had experience with this microtome beyond
seeing it demonstrated.
5.9. JUM-5 Ultramicrotome
This instrument is a product of the Japan Electron Optics Laboratory
Co. Ltd., Tokyo, which also maintains a permanent outlet in Paris. I
have very little information about this microtome beyond what is available in an advertising brochure. The microtome has a thermal expansion
drive, and the block traverses an almost circular path so that it bypasses
the knife on the upstroke, rather like the Porter-Blum microtome. I do
not have information on how this is controlled or the nature of the
bearings in this instrument. A simple, variable speed motor drive cycles
the instrument. No provision is made for rapid cycling coupled with
slow cutting speed. I have no information on minimum cutting speed
beyond the comments of an investigator who had used the instrument
and suggested that it might be comparable to a Porter-Blum microtome
operated in such a way as to give about 5 mm/sec. I do not know of this
instrument ever even being demonstrated in the United States, although
advertising brochures have been available through the Fisher Scientific
Company, Boston, Massachusetts, who are American agents for the JEM
electron microscopes manufactured by the same company.
5.10. Sorvall MT-2 Ultramicrotome
The newest fully automatic microtome is a product of Ivan Sorvall
Inc., Norwalk, Connecticut. It is an elaborate derivative of their original
Porter-Blum microtome, and continues to carry this name. Although its
introductory price is competitive with other automatic microtomes, it is
by far the most complex instrument mechanically, and it may not prove
possible to maintain this relationship.