The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1875-06-21

/ thus collected were however, carefully washed.
70 remove any OF the arsenlcal compounds which
might be mechanically attached and carefully
tested for arsenic. We failed IN every case 20
derect the slightest trace. When the plants were
ken 40 Il was found that tue tnp roots were en-
tirely des royed aud that suificlent small norous
lateral roots had be thrown out TO form tnicEly
matted mass TIE END OF che tap root or what
remained OF IT, was covered with inicS nesay
knob not very large. but apparently an extension
81 the bark OF the root
EXPERIMENTS wIVH PARIS GREEN.
About the same time We sprtnSed Paris green
upon some plants OF s.cow pear ia southern legu-
minous plano. when were a. The ume growing
in the department grounds Tue nrsi application
was TOO heavy AMI the plants were entirely
killed. second amp icaflon was made and TINS
time the leaves and terminal buds were killed.
but IN d snort time lateral Duds made Their APP
pearance leaves developed and the plants con-
tlnuea to grow very tnrlitlly. The irost threat
ered the destruction or the plants, and these
we're also collected previous to maturity. Tue
poisonous 9 mpouad, although thoroughly washed
into the ground by subse4u rams did not seed
10 have Affected the plant IN It's growth ana care
fu examination or the p ants themselves jailed 70
reveal the slightest trace Of arsenic.
From the experiments described we would infer
that arsenic is not taken Gp bg plants, anu that
arseuical compounds wen present 10 the SOIL
exert an Injurious inaaance upon vegetatol Ia
order 10 rest TINS thoroughly a. oN an opportunity
Tor the plans 3 ma IRE ana deter nine the guam
tlsy that may exist Ia tie soh without having
notably INJURIOUS influence, 1 ms ituted tue fol-
l0WIn. experiment.
NUMBER or COMMON FLOWER soTs
twaat ARE called seyen-lnch pots) OF the same size
were selected and nearly filed win measured
quantity 81 soll With the soil or each pot was
thoroughly intermixeo given quantity OF Paris
green Tao hrst pot Of the series contained 100
mlligrlmmes OF the poison. the second 200, the
third 800. the quantity Ia each pot respectively
was thus greater by 100 milligrammes than that
IN the pot immediately preceding IT. When the
quantity reached one gramme the increase was
more rapid and the succeeding lots contained re-
spectiyey two. three, tour ana five grammes of
the poisonous compounI. When the series was
complete, peas hicn had been so selected "a 10
secure those Of nearly possible the same size
and appearance were planted IN each OF the pots.
THIS experiment proved unsatisfactory on account
or the act thar on one nigat that portion OF the
greenhouse IN winch the pots were placed became
TOO cold and some Of the seeds fai ed 10 terminate.
they were not disturbed. however, lurtneT than to
remove them to a warmer portion OF the green.
house sno another series OF pots we're prepared N
4 manner similar 10 thar already described. Az
this time 1t wss considered OF some value to de-
rermine the influence or arsenite or potassa ana
arsenlate or potassa In the same way, and two
other series or pots, containing these two com
pounds respec,iycls, were prepared and placed
alongside The Cthers The growth or the plants
in these series was very satisfactory, though not
BY any means similar In all cases. Beyond GER
tain limits tile plants were anected In proportion
70 me increased quantity OF poison IN the pots.
Thus, In case Of Paris green, no de-ided action
seemed 10 take place until tae amount present
was 500 mIugrammes. ana IN the other pots o.
TINS series the pants became smaller according
10 the increased quantity or the poison IN the
pots. In these three series l employed SIX
inch pots, aud the quantity 81 soil In each was 9l.6
cubic inches. The seeds terminated AMI grew
until the quantity Of the arsenical compound
present amounted 70 Two grams In TINS quantity
Of s3ll. when The seeds decaTed IN the ground.
With the arssnlte and arseniats 81 poIsssa the
eject was very similar. Tne influence Ct these
compounds seems, however, to be more active
aud IN case or srsenite tue effect IS quite marked
wnen the soil contained so milligrammes.
The arseniatc seems. however, 70 affect the plant
when present III very small quantity, as was shown
~ comparison with plant grown A pit con
tanning perfectly normal sol, waicn, Nv the way,
was standard OF comparison Tor the otner series
also. FIR pracucal purposes, however. the effect
being so slignt need not be taken into account
untn ths quantity producing il amounts to 200 or
20l milIgramneL Ca,cui1ting upon this basis
We nnd that the limit o. tho quantity OF Paris
green that may exist IN the son without injury to
vegetation Is about 1855 grains per cubic foot,
which ~ equiva ent 70 about 90 pounds per acre,
calculating for a Geptn Or one foot. IN the same
way VIC ana that tie Limit for arseni'e or rolassa
II about 500 pounds per acre, ana though the effect
OF arseniate o. pofassa may BE noticed when only