236 LEVINE: STUDIES ON PLANT CANCERS—IV 
larger. Id gave approximately the same results as Ib (see 
TABLE). 
When the axil of an upper leaf of a decapitated plant was 
similarly treated, the average size of the crown gall for the four 
AVERAGE SIZE ** OF CROWN GALL ON TOBACCO RESULTING FROM INOCU- 
LATIONS WITH VARIOUS EMULSIONS OF BACTERIUM TUMEFACIENS 
Emul- Leaf 
sions | Character Mid. axil of 
and and Age of | No. of | vein o. of | Stem|| No. of | Leaf || No. of | decap- 
dilu- jcamtiey culture | plants | leaf ale plants | axil || plants | itated 
tions plants 
No. I 
a 1 drop 5 I.5 22 1.8 10 2.3 
b trocar j21 days be) 2.2 9 1.9 
c method 7 a8 8 27.4 
d 8 <0 10 2.7 
di 0.8 cc.* 20 1.9 
No. J 
II tis 
exe meade 9 og 
c pricks |2r1 days 12 r.5 
al \ I drop tro- 12 1.9 
ci} { jcar jaa 16 2.3 
No. III 
a Ss: 0.3 5 1.6 
b I drop i 5 0;3 5 1.06 
c trocar |21 days 5 0.3 5 0.6 
d method 5 2.3 
© 5 be 
corms | 
tdrop 5-10 
needle j21 days 6 0.9 
ricks 
No. 
I drop ri 10 
needle o days! 6 oO. 
vie 4 y: 5 
No. VI 
a 1 drop 5 ED ee 
b trocar 2 days 5 a7 13 £25 
c method 5 2 14 3.2 
d 5 2.6 4 1.6 
e ‘ Pe 5 
a} O25 en* ; 16 2.7 : A 
No. VII 
trocar 
' method 
a ee com | 7 davar 1s 0.7 
b co* II La 
7 Aap oan 
dilutions used was more or less uniform. The average size of 
the crown gall produced by dilution Ic was 2.3 cm. while Id 
(in which the suspension was I : 20) gave a crown gall which 
averaged 2.7 cm. in diameter. The same general results were 
obtained with dilutions of Emulsion VI (see TaBLe) when inocu- 
