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 
