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CIRCULAR No. 409 NOVEMBER 1936

UNITED STATES DEPARTMENT OF AGRICULTURE
WASHINGTON, D.C. ;

THE EFFECT OF THALLIUM ON PLANT GROWTH

By E. E. Horn, associate biologist, Justus C. Warp, associate pharmacologist,
James C. Muncu, consulting pharmacologist, and F. E. Gariouas, biologist
and director, Control Methods Research Laboratory, Division of Game Manage-
ment, Bureau of Biological Survey

CONTENTS
Page Page
aE FOCUChIONE meets been Bee ee Ne ee 1 | Experiments—Continued.
OVICW? Omlterabure == sas ee See 1 Hie ldbimvestieat] Onsen 5
EE EIMCI Tsay ee eye ie Pe ee | MOOG ITS Ons. oe ee ae 7
Laboratory investigations__ .-.---------- De deliteratwee cited s= 262. 2 aa te 2 eee j
INTRODUCTION

For more than 10 years thallium compounds have proved useful in
the control of the rat, the Zuni prairie dog, the California ground
squirrel, and certain rodents that have been found particularly
difficult to combat by other means. Several reviews have appeared
discussing general features of the action of thallium and of its use in
rodent control (7, 12, 19).1 Béttger (3) reported it to be widely
distributed in the vegetable kingdom, finding it qualitatively in cer-
tain mineral waters, wines, tobacco, beets, and chicory, but no pub-
lished data have been found showing the occurrence of thallium in
the soil. Buschke and Langer (6) stated that plants may take up
thallium from the ground, since they found traces in the plant ash,
and that if rat poison should be used on field or garden the thallium
would pass into the plants and might cause poisoning.

The question has been raised in several recent papers whether
thallium applications to pasture lands in the control of ground squir-
rels under field conditions will prove harmful to crop growth (4, 8,
14, 15). This subject has been studied in detail for more than 10
years, and the official agencies engaged in the distribution of thallium-
treated material have always had this in mind (/2).

REVIEW OF LITERATURE

A detailed search of the literature shows that it is not possible to
make any arbitrary statement regarding the toxicity of thallium to
plants or animals, unless a number of circumstances are considered.
Detailed data found in this search are recorded in table 1, with
corresponding references to the literature, and results obtained by the
authors also are included.

1 Italic numbers in parentheses refer to Literature Cited, p. 7.
78716°—36 1

Ds CIRCULAR 409, U. S. DEPARTMENT OF AGRICULTURE

TaBLE 1.—Action of thallium on plant growth

[Data from literature indicated by references; concentrations calculated as parts of Tl per million]

Concentration affecting growth :
Litera-
“s . ture
Test plants and materials Medium i rote
Stimulates Nor Retards ee or | ences!
Bscherichiarcolisee 2 WWiater2s2 see es pecan ai tanita) EA A Shee 800 §
Bacillus lactic acid_______- NG Uy Was wee 0.1 1.0 12.5 1, 500 22
Fomes annosus__--------_- Gulturetoee 22825 ea ees oe eee ee OS 180 2
IMO] agian pisas ee nes ee AGarjellyn 22-2 [ae ee eet a es 16 16-160 10, 18
WViGASISSa i ee Oe ee 2 Asparagine________ ~08-8..0' }--- =: SOs See eae 91
AD Yoh ee ee i ie Suga eee 800-2, 000 |------ 2; 000324. 3 eae 22
Lepidium sativum _-____-_-- OU Sae oo 2 ee oe Ne Ie i | 340 9
WaciarfabG eee a eine Wiaters(Gistilied)) ss | =a aes ase eres 20g | ae 2 os oeeret 20
eu pinws albuss= 222 ee eee doer ses eeee eegee ee ae (eu sees 20 neon Sete 20
COL LY Sy ee nas aes |e ees OMe See 2 a ee ea goer eee | ae PAU a ete ee OL BE 20
Nicotiana tabacum__-___---- Wiater28 8. Sik Sebi ee ee a ee Ty eae 16
NE) Qt Gees ME es Seat Lh Solves ee Sie tow | Sicaeevaresee heute Ae eae 25-60 a aae a ae 16
PZ CUMIN OY Soe aoe esa See eee (6 Kany penton 10 5 100-1, 00 10, 000 (2)
Triticum aestivum __-_------ Pees OMe SAB UR a ee | eee 1.5-7.0 30-80 15
Fagopyrum esculentum ____|----- O22 Sea eet [ek Bese - eae oes 1. 5-7.0 30-80 16
DIVICUICOGOISALiD C= ae | COURSE ASE EARS EE SEES Py 2 ase 1.5-7.0 30-80 16
olny Denenn Ca = | Sse Goes Rae Fees ENE ee! [eavees BGS (60 30-80 15
MSOF GIN OT aN esate ees we ees GLa ees she Wes ke Se Ns Sie ae 1.5-7.0 30-80 16
PADEN GISOLIDO Ses See elon COMMS! Bia {Scan pa aarp 22, 000 40, 000 (?) 8
Test OLULTES ee ee | eae 6 Ko rie ep el sa et : Ou eee ee 100 | 1, 000-10, 000 (3)
SAULT D: FORO AS Os || a ee GOs ts ee (0) ee | 100 1, 000 (3)
General range plants______|____- CORES pS TES esaerin gir tiptoe 8 20-60 80} @)

1 See footnote 1, p. 1. silenaee
2 Also personal communications from Moir.
3 Authors’ data.

The metal thallium has a bacteriostatic action on Escherichia coli,
Bacillus typhosus, B. dysentery, 2. streptococcer, and £. staphylococet.
This action is exerted only in the presence cf oxygen and is attributed
to oxidation to the hydroxide. ‘To inhibit the growth of E. coli (8),
concentrations of thallous acetate or carbonate of the order of 1,000
milligrams per liter (1,000 parts per million) are required. Morris
(18) found that thallous carbonate has a phenol coefficient of 6.5.
Thallous carbonate, nitrate, and sulphate in a starch or farina agar
jelly preverited the growth of various mold fungi (10, 18). Organic
thallium compounds were ineffective. In checking the growth of
the fungus FPomes annosus, Bateman (2) found that thallous sulphate
was half as toxic as mercuric chloride and three times as toxic as
silver nitrate.

Schulz (23) showed in 1886 that thallous sulphate or tartrate in
sterile gelatin meat broth or sugar solution had a marked effect upon
the activity of yeasts. In 5 hours yeast growth on sugar solution
(measured by CO, production) showed definite stimulation. In a
similar study, Richet (22) made more than 2,500 tests of the influ-
ence of thallous nitrate on lactic acid fermentation. He showed that
there is a sudden hereditary mutation of the organism. Concen-
trations of 2,750 mg per liter appeared to be the upper limit of habitua-
tion. Habituated organisms showed decreased growth in thallium-
free media.

The growth of yeast is stimulated by low concentrations of thallium
salts, but inhibited by strong solutions (17, p. 456; 21; 22). Richards
(21) found that thallium may be one of the growth stimulants for
yeast that has been referred to as ‘bios’, but on account of its
toxicity it should not be added to a medium when yeast is to be used

EFFECT OF THALLIUM ON PLANT GROWTH 3

as a food for man. Certain samples of commercial asparagine
contained thallium.

The effect of thallium compounds on the germination of seeds and
the growth of plants in pot cultures has been reported (9, 13, 15,
16, 20). Germination or growth of the seed of Lepidium satiwum
was completely prevented by 340 parts of Tl per million (9). Seed-
lings of Vicia faba, Lupinus albus, and Zea mays showed slight growth
but died in2to4days. Practically all the thallium had been resorbed
from solution in 24 to 72 hours. In the same concentration in Shive’s
solution, plants exposed to thallium compounds grew nearly as well
as the checks, and the thallium concentration was unchanged during
10 days. There was no relation between the quantity of thallium
present and the development of the root surface. Equimolar solu-
tions of cadmium nitrate, chloride, or sulphate were more toxic than
thallium solutions (20). In solution or pot cultures certain con-
centrations of thallium salts produced symptoms resembling ‘‘french-
ing’’ in tobacco plants. In many instances the stem was killed at the
surface of the soil. This was attributed to the direct application of
the solution, which was not leached to any considerable extent from
the surface layers (16). The growth of wheat, buckwheat, alfalfa,
rye, and soybean plants was slightly retarded by 1.5 to 7 parts of
Tl per million (table 1). Wax beans were somewhat more resistant.
The injury was greatest in sandy loam soil. Leaching did not pre-
vent the harmful action that appeared to be associated with an
alteration in the base equilibrium, with the liberation of aluminum
and calcium (18).

Perhaps the most striking results in studies of the toxicity of various
metallic salts to seedlings have been attained with copper sulphate.
These results are of special interest because of the wide-spread use of
copper compounds as fungicides. Kanda (/1) reported that
0.000,000,0249 percent solutions of copper sulphate (a concentra-
tion of 1 in 4,000,000,000) definitely checked the growth of seedlings
of peas, broadbeans, and buckwheat. No comparable studies on
thalium compounds were reported by him, but this would suggest
that copper is several hundred thousand times as poisonous to the

growth of plant seedlings as is thallium.
Brooks (4, p. 106) stated that a bait containing 0.5 g of thallous
sulphate was suspended on stakes a few inches above the grassy slope
in an arboretum in the Hawaii Sugar Planters’ Association in July
1929. In July 1931 there was a patch of bare earth 1 to 3 feet long
and perhaps one-third as wide.

Not a single trace of plant life was or had been apparent on these areas during
the intervening 2 years * * *. One bait, containing 0.5 gm of TlSQOu,,
would under average conditions sterilize not less than half a cubic foot of soil.

He concluded: Continued scattering of thallium sulphate baits will
presumably lead to: ‘‘(a@) complete denudation of numerous small
areas of pasture or range land * * * (6) General toxicity or
complete sterility of cultivated land * * *.” This was so
greatly at variance with the writers’ observations in California and
elsewhere, where thalgrain (grain coated with 1 pound of thallous
sulphate per 100 pounds) has been exposed, that contact was estab-
lished with the Hawaiian authorities to learn more about. this.

4 CIRCULAR 409, U. S. DEPARTMENT OF AGRICULTURE

Barnum (1) showed that the concentration of thallous sulphate
proving effective was 1 pound per 1,000 pounds of grain, or one-tenth
of the concentration needed for effective control in California. He
furnished the following statement: :

The observed and much heralded destruction of vegetation which has been
reported from Hawaii was induced unintentionally by myself as follows: At the
request of Dr. H. L. Lyons of this Station, poison bait was prepared in July
1931, to control a small population of mongoose in the Manoa Arboretum.
These animals threatened extinction of a number of imported birds released
sometime prior in this region. The preparation was made by mixing 1 lb. of
ground fresh meat with 32 gms. of TlSO,. From the mixture torpedoes, each
containing 1 full spoon of the mixture, were made of small sheets of paper. The
torpedoes were distributed in suitable places, near wooden markers, in the
Arboretum. Some were eaten; others remained and decomposed in the grass,
kept green by the daily rains. Small areas of grass surrounding these uneaten
torpedoes were killed and the areas remained denuded for several months. I
have never seen the same effect following thallium-wheat applications in corn-
fields. The dosage in the meat balis was much higher than that commonly used
in treatment of grain. The protein mixture may have been toxic in itself.

A small test was laid out wherein 0—-5-10—-15 gms. of Tl,SOs per L. of water
were applied to grass spots of approximately 1 sq. yd. each, but no permanent
toxic herbicidal values were obtained.

Of personal communications received from a number of individuals
who have used thallous sulphate mixtures, a typical report is that of
John T. Moir, manager of the Koloa Sugar Co., Koloa, Hawaii:

We have never noted any damage to field crops attributable to the thallium-
sulfate-poison rat baits. The bulk of our rat bait is distributed along field edges.
As a result the same areas have received repeated doses although not in the
same exact spot, perhaps. No killing of vegetation has been noted. In fact,
weeds continue as strong as ever. ;

While this investigation was in progress, Crafts (8) published an
abstract of his studies on the effect of thallous sulphate on four Cali-
fornia soils. He found that soils varied in their power of fixing thal-
lum. Thalgrain had no effect on the germination or growth of oats
one-half centimeter away; if one-fourth centimeter away, growth was
reduced. ‘‘Except where the dosage was excessive, oat seedlings were
unaffected by the application of treated barley to the soil, followed
by irrigation.”’ The heaviest application, equivalent to 27 pounds of
thallous sulphate per acre, reduced growth less than 50 percent. The
application of 5,000 pounds of poisoned grain per acre might sterilize
the top 1.5 inches. However, the average initial dosage of poisoned
erain is only one-third pound per acre, and this is decreased later to
one thirty-fifth pound or less. He concluded:

The success of this material should permit similar reductions in other regions,
so that the amount of chemical becomes totally insignificant so far as soilsteriliza-
tion is concerned. The writer observed no loss in fertility in range lands success-
fully treated for 5 successive years. The only denuded areas found were the
open burrows, fresh mounds, and beaten trails of squirrels in untreated fields.
Regardless of other objections to thallium compounds in rodent control, the

possibility of losing agriculturally valuable land through sterilization seems
remote.

EXPERIMENTS

In order to determine the effect of thallium on plant growth under
controlled conditions, a double investigation was undertaken, one
part in the laboratory and the other in the field. :

2 Personal communication, Sept. 12, 1933.
3 Personal communication, Apr. 2, 1932.

EFFECT OF THALLIUM ON PLANT GROWTH a
LABORATORY INVESTIGATIONS

Experiments on a laboratory scale were conducted on loam soil in
trays and in pots at Denver, Colo., over a period of a year. In series
1, the seed of peas, sweet corn, field corn, clover, and timothy were
planted in trays 6 by 6 by 3 inches.

In control trays these were allowed to germinate over a period
of 2 months, which established the rate of normal growth. On the
sixty-first day a solution contaiming 49 mg of thallium (Gn the form
of T1,SO,) was applied once to each tray. This represents the average
quantity of thallium that might be applied in an ordinary bait spot
of thalgrain placed in ground-squirrel control. No detrimental effects
on plant growth were noted in these trays.

Seeds in other trays were handled similarly, except that 49 mg

of thallium per tray were mixed with the soil before the seeds were

planted. Germination was delayed and reduced in all these trays,
and after slow growth all plants died.
- Seeds in other trays were allowed to germinate and grow nor-
mally for 12 days and then were irrigated with a solution containing
100 mg of thallium per liter Gn the form of TI,SO,) on the twelfth,
twentieth, twenty-seventh, and thirty-third days. Each irrigation
contained 100 mg of thallium, so that a total of 400 mg of thallium
was applied to each tray over a period of about a month. This com-
pletely inhibited vegetative growth.

These laboratory results suggest that thallium is toxic to the

germinating plant but not to the growing plant, except in strong

concentrations.

In series 2, in a large mixer, 0, 5, 10, 100, 1,000, and 10,000 mg of
thallium per kilogram (as Tl,50,) were thoroughly mixed with loam
soil and three lots of each were placed in 1-gallon jars. The surface
soil was then prepared for planting, and 12 corn seeds, 1 g of timothy,
or 1.5 g of clover were planted in each jar. The 18 jars were then
watered from time to time. With the soils containing 5 and 10 mg
of thallium per kilogram the growth of corn was definitely stimulated;
the clover was somewhat less stimulated; and the timothy showed
some slight stimulation in later growth. Im soils containing 100 mg
per kilogram or more, toxic effects were noted with all seedlings. A
concentration of 1,000 mg per kilogram stopped the germination of
timothy, and 10,000 mg per kilogram stopped the germination of
corn and clover. These results would suggest that thallium is benefi-
cial to plant growth when present to the extent of 5 to 10 mg per kilo-
gram of soil; that the toxic effect begins to develop with concentrations
of 100 to 1,000 mg per kilogram; and that 10,000 mg per kilogram of
soil are necessary to prevent germination.

FIELD INVESTIGATIONS

Field studies were made on typical areas of plant growth in Cali-
tornia, the thallium being applied in the form of thallous sulphate
directly to the soil, either as a dry salt, in irrigation water, or as
thalerain. The regular thalgrain for ground-squirrel control was used
in these experiments, and only the thalgrain results are incorporated
in this report. Every attempt was made to duplicate the conditions
under which it is commonly employed in rodent-control operations,
to learn what damage (if any) might follow routine rodent-control

6 CIRCULAR 409, U. S: DEPARTMENT OF AGRICULTURE

procedure. In the original treatment of an infested area an average
of 1 pound of thalgrain per acre is used for the first treatment, and
one-fifth to one-tenth pound per acre on subsequent treatments.
Normally 27 g of thalgrain are distributed over an area of 2 to 4
square feet around ground-squirrel burrows. Since 1 pound of thal-
grain is sufficient for 16 bait spots, it will actually cover 32 square
feet, on the basis of the strongest concentration. If the entire acre
were covered, approximately 13 pounds of thallous sulphate, or 10
pounds of thallium, would be required.

In March 1932, on a typical range area in Santa Clara County,
Calif., 8 quadrats with suitable checks were established, each quad-
rat 2 feet square. All vegetation in each was listed and mapped for
density and for percentage of the entire vegetative growth, density
being tabulated on the basis of 10 as complete coverage. On these
quadrats the soil was Altamont clay loam, but comparative studies
with other types of California soil gave identical results.

The quantity of thalgrain applied to each quadrat and the thallium
content are given in table 2. There was no rain from March 1932,
when the thalgrain was distributed, until the followmg December.
No damage was detected to any plants growing in the quadrats; all
developed, matured, and died on the treated as well as on the control
- quadrats. In March 1933, following the winter rains, or 1 year
after the distribution of thalgrain on the quadrats, the composition
and the density of vegetative growth was redetermined for each
quadrat and compared with the original values.

TABLE 2.—Fffect of thallous sulphate upon density of vegetative growth

Vegetative den- Vegetative den-
7 sity Nae | atta, sity Shera
-_| Thallous cover ar allous cover

Quadrat no. cheer Sulphate! 28 oes Es |e Quadratino: See ea Sulphate ||esic ees ee beers
Pp per acre | Pp *~ | per acre

Origi- | After 1 Origi- | After 1

nal year | nal year

Pounds | Pounds Pounds | Pownds

j a ee OS 0 0 10.0 TSO ia eee ee oe 3. 000 50 8.0 0.3

2eE ee 1, 000 10 7.0 SHON Gee we oes ae 7, 500 75 8.5 a8;

SORE Eten: , 000 20 6.0 PaAV || Paranal eet 10, 000 100 8.5 pall

EI oR a 3, 000 30 7.0 aia ase eee ea ae 20, 000 200 7.0 Aik

|

These quadrat experiments show that very high concentrations of

thalgrain, when left on the surface of the ground throughout a year
cause inhibiting effects on growth of vegetation. A marked decrease
in plant growth was observed following the application of 3,000
pounds or more of thalgrain per acre. Some decrease in vegetative
growth was observable when 20 to 30 pounds of thallous sulphate
per acre were applied, corresponding to 2,000 to 3,000 pounds of thal-
erain per acre. In interpreting these figures it must be remembered
that in control work the maximum application of thalgrain in the
original treatment is only 1 pound per acre, but that this is applied
to so limited a portion of the entire surface that it would correspond
to approximately 1,000 pounds of thalgrain per acre if the entire
area were covered. This quantity caused a slight stimulation in
vegetative growth on the treated quadrat. It must also be remem-
bered that thalgrain is distributed only when the animals to be con-
trolled will take it rapidly. Usually nine-tenths of the baits are eaten

EFFECT OF THALLIUM ON PLANT GROWTH 7

during the first day, and practically all within a week. Therefore,
the aidbuted thallium is removed from the surface before it can
produce any effect on the vegetation.

Repeated studies of range areas treated as often as nine times
failed to show any damage to vegetation. With removal of the
ground squirrels the soil returns to a proper condition, and normal
plant growth rapidly occurs. In general, the use of thallium in
rodent control has consistently increased the (grow th of vegetation
from 10 to 25 percent, without any evidence of damage to soil fertility.

A few experiments were conducted to determine whether thallium
compounds would prove suitable as weed killers. Azbes were placed
in pots of soil and treated with varying concentrations of thallium,
up to the rate of 1,280 pounds per acre. No injurious effects were
observed over a period of 8 weeks. This suggests that such hardy
plants as Ribes are more resistant than grains and grasses.

Assuming, for comparative purposes only, that the action of applied
thallium would be localized in the upper 3 inches of soil: Then, 1
acre, or 43,560 square feet, one-fourth foot deep would correspond. to
approximately 10,000 cubie feet of soil and would weigh approxi-
mately 1,000,000 pounds. Under this assumption, 10 pounds of
thallous sulphate per acre would correspond to 10 parts per million,
and the results on a field scale are in harmony with those in the

laboratory.
J CONCLUSIONS

Under laboratory and field conditions on various types of soil, the
addition of thallium compounds up to 10 parts per million (10 pounds
of thallous sulphate per acre, equivalent to 1,000 pounds of thalgrain
per acre) had no injurious effects on vegetation, and in many instances
appeared to stimulate plant growth.

With the application of larger quantities, injury was observed.
Under field conditions no damage occurred during 9 months of dry
weather, but it developed following the rainy season.

Thallium compounds when applied to the soil in varying concen-
tration up to 1,280 pounds per acre failed to kill or apparently even
to injure fibes in 8 weeks.

In control work, ground squirrels consumed thalgrain so rapidly
that no damage to plant growth was found on areas treated as fre-
quently as nine times.

Under the conditions used in the control of rodents by properly
trained personnel, no evidence of injury to vegetative growth by
thalgrain has been found.

LITERATURE CITED

(1) Barnum, C. C. ;
1930. RAT CONTROL IN HAWAII. Hawaii. Planters Rec. 34: 421-4438.
(2) BaTEMAN,

1933. THE EFFECT OF CONCENTR ADS ON THE TOXICITY OF CHEMICALS TO
LIVING ORGANISMS. U.S&. Dept. Agr. Tech. Bull. 346, 54 pp.
illus.

(3) Borreer, R.

1863. UBER DAS VORKOMMEN DES THALLIUMS IN SALINISCHEN MINERAL-
WASSERN, INBESONDERE IN WASSER DES NAUHEIMER SPRUDELS.
Liebig’s Ann. Chem. 128: 240-247.

(4) Brooks, S. C.

1932. THALLIUM POISONING AND SOIL FERTILITY. Science (n. s.) 75:

105-106.

§ CIRCULAR 409, U. S. DEPARTMENT OF AGRICULTURE

(5) Buscuxs, A., and JacoBsoun, F.

1922. UNTERSUCHUNGEN UBER THALLIUMWIRKUNG. Deut. Med. Wehn-

_ sehr. 48: 859-860.
(6) —————— and Lancer, E.

1927. DIE FORENSISCHE UND GEWERBL.-HYGIENISCHE BEDEUTUNG DES

THALLIUMS. Miinchen Med. Wehnschr. 74: 1494-1497. }
(7) ——————_ and_ PEtsEr, B. ;

1931. DIE BIOLOGISCHEN WIRKUNGEN UND DIE PRAKTISCHE BEDEUTUNG
DES THALLIUMS. Ergeb. Allg. Path. u. Path. Anat. des Men-
schen u. der Tiere 25: 1-57.

(8) Crarts, A. S

1934. THE EFFECTS OF THALLIUM SULFATE UPON SOILS. Science (n. s.) ©

79: 62. ;
(9) Dinuine, W. J.

1926. INFLUENCE OF LEAD AND THE METALLIC IONS OF COPPER, ZINC,
THORIUM, BERYLLIUM AND THALLIUM ON THE GERMINATION OF
srEps. Ann. Appl. Biol. 13: 160-167, illus.

(10) Farcuer, R. G., Gauttoway, L. D., and ProsBert, M. HE.

1930. THE INHIBITORY ACTION OF CERTAIN SUBSTANCES ON THE GROWTH

OF MOULD FUNGI. Shirley Inst. Mem. 9: 37-52.
(11) Kanpa, M.

1904. sTUDIEN UBER DIE REIZWIRKUNG EINIGER METALLSALZE AUF DAS
WACHSTHUM HOHERER PFLANZEN. Jour. Col. Sci., Imp. Univ.
Tokyo 19, art. 13, 37 pp., illus.

(12) Kettoge, E. S.

1933. THE CALIFORNIA GROUND SQUIRREL CONTROL PROGRAM. Calif.

Dept. Agr. Spee. Pub. 109, 21 pp., illus. }
(13) Knop, W. ;

1885. UBER DIE AUFNAHME VERSCHIEDENER SUBSTANZEN DURCH DIE
PFLANZE WELCHE NICHT ZU DEN NAHRSTOFFEN GEHOREN. K. |
Sachs. Gesell. Wiss. Ber. tiber Verhandl., Math.-Phys. Cl.
1885 (I-ID): 39-54. ;

(14) Lyon, M. W., Jr.

1932. THALLIUM POISONING. Science (n.s.) 75: 381-3882.

(15) McCoot1, M. M.

1933. EFFECT OF THALLIUM SULPHATE ON THE GROWTH OF SEVERAL
PLANTS AND ON NITRIFICATION IN soIts. Boyce Thompson Inst.
Contrib. 5: 289-296, illus.

(16) McMourrrey, J. E., JR.
1932. EFFECT OF THALLIUM ON GROWTH OF TOBACCO PLANTS. Science

(n. s.) 76: 86.
GE) MEA AL Ve
' 1923. UBER DIE EINWIRKUNG VON METALLSALZEN AUF DEN VERLAUF DER
ALKOHOLISCHEN GARUNG. Biochem. Ztsehr. 141: [447]-457.
(18) Morris, L. E.
1926. MILDEW IN COTTON GOODS. IV. ANTISEPTICS AND THE GROWTH OF
MOULD FUNGI ON SIZING AND FINISHING MATERIALS. Shirley
Inst. Mem. 5: 321-349.
(19) Muneu, J. C., and Sinver, J.
1931. THE PHARMACOLOGY OF THALLIUM AND ITS USE IN RODENT CONTROL.
U. 8. Dept. Agr. Tech. Bull. 238, 28 pp.
(20) Prat, S.

1932. TOXICITY OF METALLIC IONS AND THE ANTAGONISTIC ACTION OF THE
NUTRIENT SOLUTIONS. 14th Internat]. Physiol. Cong. Rome,
Proc., pp. 207—209.
(21) Ricwarps, O. W.
1932. THE STIMULATION OF YEAST GROWTH BY THALLIUM, A “BIOS”
IMPURITY OF ASPARAGINE. Jour. Biol. Chem. 96: 405-418, illus.
(22) RicHeEt, C.
1917. LA FERMENTATION LACTIQUE ET LES SELS DE THALLIUM. Ann.
Inst. Pasteur 31: 51—59.
(23) Scuuuz, H.
1886. DIE WIRKUNG DER THALLINSALZE AUF FAULNISS UND GARUNG.
Centbl. Med. Wiss. 24: 449-450.

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