The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1872-01-03
THE LIGHT OF SILENCE.


The B'ec,ro- Chemic and Spectral Analysis
Tests Their DcIicmcy, beauty and InfisIii-
biIity.
BROOKLYN, Jan. |. 1872.
To TIE EDITOR OF THE HERALD:-
10 that the medical gentlemen on the
side OF the prosecution in the Wharton case have
omitted two positive anu beautiful tests for the
presence OF antlmony OF Its salts in the analysis
made OF the stomach and other parts OF the late
General Ketchum, vz.:-First, the electro-c hemlc
and secondly that greatest Of all minute tests the
spectral analysis. Now, care not how minute the
quantity II these tests 1t must respond. In the
eectro-chemic you Will find the metal pre-
cipiated with its characteristic lustre upon
the walls OF the porcelain test YES.
sell Indeed, You can test the pro-
cess SO far as to throw of by electroysis every
drop of huid simply by divorcing the oxgen ana
hydrogen, leaving every particle OF the precipitate
residuum, then dried and the shape of po gder
or dust. Now, before the spectrum, the analysis
VIII yield positive test for any metal or SALT yea
even to one-!nillionth OF portion OF gram. why
should these important tests be omitted by either
sleY For after all, true science only yrasps the
truth.
or spectral analysis, as applied to chemistry DR..
Waterman, OF New York, has shown that the great
est physicists in Europe nave freely acknowledged
its high importance ana usefulnesS its accomp ISL
ments IN chemistry may be considered as among
the highest triumphs OF the human intellect The
material accumulated up TO the present hour bear
ing directly upon the domain OF true medical pro-
fession Is Intensely interesting and is safe to say
| that no man can clam to stand at the head OF
chemistry or medicine who lis ignorant OF the re-
suits oil spectral analysts.
The process OF making an analysis by means OF
| the spectrOsc )pe Is simple enough. Bodies he
examined arc either solid, iIuid or gases The soiids
must be brought to state OF incanaescencc, either
nNv
gen iiame, when they admit rays OF all degrees OF
relrangbllily. Fluids placed before the In
tubes also e may be- used FuGs give ABSORPTION p
bands in various parts OF the spectrum. Gases
examined ny means OIL an electric Induction spark,
which passes through their extremely attenuatcd
thermometer tube, win bulb at each extremity,
into which electrodes e Of platma Or aluminium are
alr pump naiil lls one-siS, nnndreailn or or
pressure OF the air Is lett in that state OF at.enu-
lion the gas offers very slight resistance to the
anu beautiful light OF various colors changing of
course, with the different gases employed. Thus no
| spectroscOpe
| Every known metal, alkal or alkaline earth, when
heated up to gaseous state gives OF light peculiar
| TO Itself, influencing and changing the spectrum
In manner peculiar to Itself aud to none
| OF the spectrum, with the exception OF single
bright band, OF which sodium and tnallium furnish
bright lines in various parts Of the spectrum as
barlun. casum and rubidium. The fluids show
| dark bands IN the spectrum OF various depths OF
shading, breadth and purity OF outline. These
black bands are called absorption bands. When
dcation OF the spectrum. Nome however, Is 80 rich
aud distinct IN feature, and none has attracted
more deserved attention than the spectrum OF the
blood. Important IN a practical point Is the spec.
troscoplc test OF barium ana thaliium In cases Of
reliable test TO demonstrate their presence
Tie objection That the many notifications OF the
spectrum by so great number OF substances as eau
be speclrOscOpcally examined IL liable to lead TO
confusion Is devoid OF foundation, while every sub
stance has ITS own peculiar spectrum not possessed
by any other known substance IL Is on the con.
trary, TACT that those who become acquainted
WIN The various spectra by observation do not
leave the exact measurements OF the single
constituents. The color, relative POSITION,
or band are quite characteristic to Insure ready
cognition ana exact results even In the hands OF
persons unaccustomel TO work with the spectre.
scope The exhaustive analysis OF blood by the
speclroscopic test FORMS the basis OF its appiica
sir Humphrey Davy discovered that by means OF a
glass prism the beam OF white light proceeding
OF the rainbow. Having darkened his room he
made hole In the window shutter, and placed
behind II glass prism WIZ, one OF the sharp edges
beam rom without Tell on the glass withln the wall
on The opposite side was rridescent wltn strip of
varlegated light rs " a. Slice OF bright rainbow
were clnging to II. The lower end OF the lulnin-
Gus band was a rich warm red, ana this passed by
died away, Dy deepening hues OF green into a
narrow strip OF carh blue while, at the upper end
the mango tut became warmed INTO q brilliant edg-
ine OIL violet. Here we and tine discoverer OF the
won!eri spectloscope. since his day such author
ity as Professors Krcihoft, OF Heidelberg; STOKES
Brunscu, Crooks, Reich ReIchter, of Friedberg
s sas,, Hoppeseyler, z; schmidt phaegers ex
1hudichun. Much Of this material Is directly appi-
cable To the practice of medicine.
Now, TO snow The extraordinary decacy OF the
spectrum test and 10 give an IDEA Of the sensitive
ness Of tins test las DR.. Waterman beautifully de-
monstrated, let us take Que pound Of common
table SAT- and divide IL into 500t0j parts. One of
these minute atoms OF matter Is called q MILL
gramme, The experienced chemist Is able to weigh
such % minute particle only with the most delicate
scales, and with extraordinary care ana acquired
rived at the limits Of posslbIes Again, let us
divide one OF these minute particles mo 3.UOo, COZ
parts, ana we OBTAIN an atom OF matter so minute
that the human mind IS Incapable Of forming any
presence by the spectrum test with the utmost GER
tainiy aud ease Inc busting OF q book in the re-
hottest corner OF this room Will Immediately cause
the sodium 10 dart i0rth with It's brilliant yellow iiDe
ana thus reveal the presence OF this metal
My initial ideas Of chemistry were obtained
during the analysis OF the celebrated stephens case
You Will lind the brag test, beng Marsh's with
D0remus' notification In the days gone by look
with pleasure IN my experience of this great
master IN the minute Iess ana beauty OF this test:
but, sir, IL can not Tor one moment compare with
The advances In chemistry OF our day, viZ.:-the
eectrO-chemlc and specti OscOpc, Tor after his
minlltest tests are made by Marsh's apparatus and
then The microscope rails 10 yield the ruth, lie may
then, with reliance take OF the dust that ms de-
posted his heated glass tubes (Doremls mo,iin.
cation OF Marsh) and win certainty derermine its
tlue character. Yours most respectfully,
JOHN J. CALDWELL, NJ d.
ST MAaY'S HOSPITAL, HOBOKEN