means of it in _one-third of a second_.

In the last "Annual of Scientific Discovery" are interesting notices of
photographs of the sun, showing the spots on his disk, of Jupiter with his
belts, and Saturn with his ring.

While the astronomer has been reducing the heavenly bodies to the
dimensions of his stereoscopic slide, the anatomist has been lifting the
invisible by the aid of his microscope into palpable dimensions, to remain
permanently recorded in the handwriting of the sun himself. Eighteen years
ago, M. Donné published in Paris a series of plates executed after figures
obtained by the process of Daguerre. These, which we have long employed in
teaching, give some pretty good views of various organic elements, but do
not attempt to reproduce any of the tissues. Professor O.N. Rood, of Troy,
has sent us some most interesting photographs, showing the markings of
infusoria enormously magnified and perfectly defined. In a stereograph
sent us by the same gentleman the epithelium scales from mucous membrane
are shown floating or half-submerged in fluid,--a very curious effect,
requiring the double image to produce it. Of all the microphotographs we
have seen, those made by Dr. John Dean, of Boston, from his own sections
of the spinal cord, are the most remarkable for the light they throw on
the minute structure of the body. The sections made by Dr. Dean are in
themselves very beautiful specimens, and have formed the basis of a
communication to the American Academy of Arts and Sciences, in which many
new observations have been added to our knowledge of this most complicated
structure. But figures drawn from images seen in the field of the
microscope have too often been known to borrow a good deal from the
imagination of the beholder. Some objects are so complex that they defy
the most cunning hand to render them with all their features. When the
enlarged image is suffered to delineate itself, as in Dr. Dean's views of