PENETRATION OF SWEET CORN PERICARP 
131 
for one year, is given in the first column of Table I. The effect 
of soaking the seed for varying periods at room temperature 
upon the physical penetration was also a part of the proposition 
and is shown in the remaining columns. In practically every 
case there were at least four readings taken. In the data only 
the averages are given. 
TABLE I. DATA SHOWING THE NUMBER OF GRAMS NECES- 
SARY TO PENETRATE THE PERICARP OF “STOWELUS EVER- 
GREEN^^ SWEET CORN WHEN DRY AND WHEN SOAKED FOR 
VARYING PERIODS. THE CORN HAD BEEN GROWN IN IOWA 
FOR ONE YEAR ( 1919 ) 
Dry 
8Hes. 
12 Hrs. 
24 Hrs. 
36 Hrs. 
48 Hrs. 
72 Hrs. 
Canning stage.. 
103.75 
88 
121 
93.5 
93.6 
89 
70.8 
Dented................ 
111.75 
89.5 
93 
■ 90.2 
92.6 
90.25 
107.7 
Mature 
134 
80.3 
83 
72.7 
54 
53.8 
51.2 
In the canning stage the number of grams necessary for the 
penetration is a little less than for the dented and consequently 
smaller than for the mature. On soaking the penetration force 
of the pericarp of the mature fruit is much less than in the corn 
selected at the canning period. This same relation is also apparent 
when comparing the mature and dented kernels. 
TABLE IL DATA SHOWING THE NUMBER OF GRAMS NECES- 
SARY TO PENETRATE THE PERICARP OF “STOWELUS EVER- 
GREEN’' SWEET CORN WHEN DRY, AND WHEN SOAKED FOR 
VARYING PERIODS. THE CORN HAD BEEN GROWN IN IOWA 
FOR TWO YEARS (1918 AND 1919 ) 
Dry 
8 Hrs. 
12IIRS. 
24 Hrs. 
36 Hrs. 
48 Hrs. 
72 Hrs. 
Canning stage.. 
92 
82.3 
121 
97.8 
69.4 
98.2 
68.2 
Dented 
121.5 
93.5 
93 
95.7 
70.5 
65.4 
89 
Mature 
172.75 
85 
94 
90.2 
64.75 
67.6 
87.2 
In the same variety of sweet corn grown in Iowa for two 
years the pericarp when dry is punctured by 92 grams, as com- 
pared with 103.75 grams at the canning stage; the dented requires 
121.5 and the mature, 172.75 grams. There is a wide difference 
between the three stages of development. Soaking the seed for 
varying periods from 8 to 72 hours gives results that are some- 
what diversified. 
In Table III, the differences in the penetration force between 
the different stages — canning, dented, and mature — is practic- 
ally as well marked as in the previous citations. Soaking the 
