ungstate of calcium. The observer
looks through the screen, or into it, and sees _with the unaided eye_
the invisible interior parts of the object examined, held between the
screen and the cathode light. The invisible rays take the image of the
interior parts of an opaque object, and carry that image to the
screen, where it is reconverted into visibility and delivered to the
eye of the observer, without the aid of any instrument at all! It is
on this simple principle that Edison has invented his surgical and
physiological lamp. The announcement is that with this lamp the
surgeon may look through the calcium tungstate screen and examine, for
example, the fractured bones of the hand, and set them perfectly by
actual inspection of the parts with his eye!

What then _is_ the cathode ray? At the present time its nature is not
understood. That it is a form or mode of motion goes with the
saying--unless it should be presently shown that all the imponderable
forces are really _material_ in their nature; that is, that they are
an inconceivably fine and attenuated form of matter in varying
manifestations.

The cathode rays are not light. They are not sound. They are not
electricity or magnetism. They are not heat. They are not any of the
known forms of force. They seem to be a new transformation of some one
or more of the known agents. It has long been observed that _motion_
is accompanied with _sound_, and that motion also, if increased,
becomes manifest in _heat_. It is known that heat is convertible into
light, and light into electricity.

It is possible that at the bottom of all these phenomena lies the
force of gravitation. This force is absolute and universal. All the
others are partial and limited. All the others, even the newly
discovered cathode rays, are subject to obstruction by certain forms
of matter; that is, to them certain forms of matter are opaque. But
gravitation knows no opacity in the universe. No atom of matter is
exempt from its sway. It streams through all obstructive media as
though such media did not exist. It would appear that heat, light,
electricity, sound, the cathode rays, and all other forms of force in
nature are probably variations, and as it were limited expressions and
manifestations, of _the one supreme force_ that supports the
constitution of the physical universe; and that one supreme force is
_gravitation_!

Stages in Biological Inquiry.

THE NEW INOCULATION.

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