8 
BULLETIX 1029, U. S. DEPARTMENT OF AGRICULTURE. 
increase in length of formaldehyde treatment. Injury to the seedlings 
is evident first from delayed germination and later from various 
degrees of retardation of growth. A slight check at the outset may 
be overcome within a few days, but increase in the severity of 
treatment results in permanent stunting. Accompanying the latter 
there is usually definite injury to the cotyledons, which remain 
dwarfed and become distorted in shape. Oftentimes with milder 
treatments this injury is confined to that cotyledon adjacent to the 
seed coat, while the other develops normally. 
Table II. — Effect of formaldehyde solution upon the black-leg fungus icithin in- 
fected cabbage seeds and upon commercial seeds. 
Length 
of time 
in the 
solu- 
tion 
(min- 
utes). 
Subsequent 
treatment. 
Effect upon infected seeds. 
Effect upon com- 
mercial seeds. 
Strength and temperature of 
solution. 
Seed 
lot. 
Num- 
ber of 
seeds 
used. 
Seeds 
with 
viable 
fungus 
after 
treat- 
ment 
(per 
cent). 
Seeds 
with 
viable 
fungus 
and 
germin- 
ating 
(per 
cent). 
Germina- 
tion (per 
cent). 
Seed 
ling 
in- 
jury .& 
Seed 
lot 
2-18.o 
Seed 
lot 
3-lS.o 
Untreated 
4-18 
1-19 
1-19 
4-18 
4-18 
4-18 
1-19 
1-19 
4-18 
4-18 
4-18 
1-19 
4-18 
130 
24 
10 
24 
25 
25 
15 
23 
25 
25 
25 
24 
25 
75.3 
66.6 
50.0 
33.3 
16.0 
16.0 
60.0 
13.0 
24.0 
16.0 

8.3 

22.3 

10.0 


8.0 
13.3 

4.0 
4.0 



93 
97 
o 
Strength 1 to 256 
At room temperature 
30 
37 
15 
30 
30 
30 
45 
60 
60 
120 
120 
1 
I 
I 
5 
Rinsed 
...do 
...do 
...do 
...do 
Unrinsed . 
Rinsed 
...do 
Unrinsed . 
Rinsed 
Unrinsed . 
...do 
...do 
...do 
...do 
...do....... 
Do 
Strength 1 to 128: 
At room temperature 
92 
90 
85 
98 
"96" 
O 
o 
Do 
e 
Do 
Do.... 
66 
79 
78 
57 
48 
46 
45 
46 
28 
32 
22 
20 
80 
85 
88 
69 
+ 
Do 
Do.... 
+ 
Do 
+ 4- 
Do 
++ 
Do 
+ + 
At55°C 
+ + 
Do 
+ + 
Do 
-f + 
At60°C 
+ 4- 
Do 
4-4- 
Do 
...do 
+ + 
« Wisconsin Hollander variety grown at Racine, Wis., in 1918. 
& Symbols used: Q= No injury; ©= slight; -r-=medium; 4-= severe; 
= very severe. 
Table II shows that severe injury with 1 : 128 formaldehyde solution 
resulted with one hour of treatment when the seed was subsequently 
rinsed and with 30 minutes when the seed was dried without rinsing. 
It is also shown that, although materially reduced, the fungus had not 
been completely eradicated from infected seeds by either of these treat- 
ments. Complete disinfection was not attained with rinsed seed even 
after two hours of treatment and only after one hour with unrinsed 
seed. It is worthy of note that the infected seeds were killed some- 
what earlier than the invading fungus, and this in practice might 
reduce somewhat the number of primary infections. It will be shown 
later, however, that infected seeds although incapable of germination 
