New-York tribune., 1905-01-22

of optical instruments. One. described in consular
reports received in this country about eighteen
months ago. was suggested by Professors Zsig-
mondy and Siedentopf. 1t consists essentially of
new method of illuminating the particles to be ex-
amined. Any good microscope stand can be used
but the tube must be adjusted in a vertical posi-
ton. The objective. object glass. needed is one
suited to immersion in fluid. Immediately below
the objective is a tiny trough with transparent
walls. and fed from above by rubber tube. The
things to be studied suspended in the fluid, and
find their way to the trough through gravitaton-
The eyepiece employed is adapted to visual
work. with attachments which perform special
service. but which need not be considered here.
The operator discards or ignores for the time the
mechanism commonly used to throw light upward
from below the stage through hole in the latter.
Instead. he employs train of devces-enses.
screen with Il slit in it and illuminating OBJ
jectve-to bring beam of light horizontally to his
trough. The best source of light when the is
available is arc lamp, so enclosed that no
rays escape except those which travel this pre-
scrbed path. The concentrated beam derived in
the manner described is directed right angles
with The line of vision and enters the trough just
above the surface of the stage.
1t is not possible to set precise information about
the degree of Improvement effected by this sys-
tem Perhaps the gain is not more than 80 per cent
but there is no doubt that much detail is rendered
visible whlch-woud be beyond the power or the pest
microscope If the older methods OF illumination
The other innovation is more modern. and few
persons in America have yet heard of it,. To some
but it utlzes an entirely principle. The light
ing of a specimen is managed in somewhat the
dnarv sIInIehT i anaIvzed nv prism the observer
sees all the cOors OF the rainbow At one end of
the series is violet band and at the other red
shorter than the others. Out beyond the visible
violet rays are others having still shorter wave
length, but ordinarily unseen. Glass obstructs
them. but prism Of quartz transmits them These
Of lines in the solar spectrum which he cannot
substitute quartz for glass in the train Of lenses
interposed between the arc light and the specimen.
light the latter being particularly useful for OBJ
tanning photograph Of a specimen The wave
lengths of the visible spectrum range from O76
waves TO which the highest efficiency in this par
teular work Is attributed have length of 0275
a lnIcr9n. In actual practice the operator uses
stand equipped with mechanism which enables
piece needed in focusing visualy and to Substitute
therefor a camera An additional merit of the plan
DR. Dr, George F. Kunz. OF this city. who for many
years mas been familiar with other applications OF
Ultra u violet rays to scientific research. and who
of the first Americans to learn of this system STs
end speaks enthusiastically about its value He
says that it practically doubles the power Of a
microscope. He is under the Impression that no
experiments nave yet been made in this country
many it has revealed pecularities Of structure in
animal and vegetable specimens that were pre-
gy Nt3gGsiy unknown 1t seems 10 give higher Ere
sowing power to the microscope than has hitherto
Deeh developed. DR.. kunz's own special depart
S Ineht OF study 1t is hardly necessary TO say Is
ninefalOgy. Whether research in that direction
VIII De promoted by the methods proposed in Jena
ne Is not able to tell.
1t is interesting recall in this connection soma
suggestions offered by Dr, Kunz in 1903. in re-
porrng the examination made by himself and
Professor baskerville OF variety OF huorescent
numerals when exposed TO the actions OF Y rays,
ultra violet light and radium Though not a phy-
sician, himself he alert to the possibility
tnat medical men might utilize the phenomenon
or huorescence TO discover diseased conditions in
side the body. lie proposed to administer harm
substances with
through LESSONS, and by their position tas re
chief existed He also foresaw the chance that n
injected into the blood. such drugs could be madc
to glow under the influence OF ultra violet rays
or rad