470 
Kidd and West . — The Controlling 
The results thus obtained are tabulated below : 
Table XIII. 
Results of Experiments on the Permeability of the Seed-coats of White 
Mustard Seeds to Oxygen . 
Remarks . 
Testa from an inhibited seed. 
Testa from a non-inhibited seed. 
Both inner and outer testas present. 
Exper. i. 
Rise of KOH columns after an interval of: 
\ hr. ij hrs. 3^ hrs. 4^ hrs. 
6 mm. 12 mm. 23 mm. 25 mm. 
6 mm. 12 mm. 28 mm. 31 mm. 
Temperature I5°C. 
Remarks. 
Testa from an inhibited seed. 
Testa from a non-inhibited seed. 
Both inner and outer testas present. 
Remarks. 
Testa from an inhibited seed. 
Testa from a non-inhibited seed. 
Both inner and outer testas present. 
Remarks . 
Testa from an inhibited seed 
Testa from a non-inhibited seed. 
Both inner and outer testas present. 
Exper. 2. 
Rise of KOH columns after an interval of : 
1 hr. 1^ hrs. 2 hrs. 
9 mm. 11 mm. 15 mm. 
7 mm. 9 mm. 12 mm. 
Temperature i5°C. 
Exper. 3. 
Rise of KOH columns after an interval of: 
1 hr. i§ hrs. 3 hrs. 
9 mm. 11 mm. 20 mm. 
7 mm. 9 mm. 17 mm. 
Temperature I5°C. 
Exper. 4. 
Rise of KOH columns after an interval of: 
20 hrs. 24 hrs. 40 hrs. 
42 mm. 62 mm. 72 mm. 
43 mm. 63 mm. 73 mm. 
Temperature I5°C. 
Exper. 5. 
Remarks. Rise of KOH columns after an internal of : 
20 min. 40 min. 60 min. 80 min. 100 min. 120 min. 
Testa from an inhibited seed. 4 mm. 13 mm. 21 mm. 28 mm. 47 mm. 53 mm. 
Testa from a non-inhibited seed. 7 mm. 15 mm. 24 mm. 34 mm. 56 mm. 66 mm. 
Inner testa only present. Mean temperature of laboratory, I5°C. 
NB. — During these experiments the height of the barometer showed no appreciable change. 
It is to be noted that the series of experiments dealing with the 
permeability of the testa to oxygen are less satisfactory inasmuch as single 
testas only are compared, and, moreover, a considerable amount of handling 
is unavoidable in setting up the experiments. In the series of experiments 
dealing with the permeability of the testa to carbon dioxide, the average 
effect of a number of seeds is measured and the seed-coats are intact. 
The outstanding result of the above experiments is that the testa of 
White Mustard seeds, both in the inhibited and non-inhibited condition, is 
very permeable to oxygen and carbon dioxide. It cannot be said, however, 
that the experiments show that the testa of the inhibited seed is less 
permeable to either oxygen or carbon dioxide than that of the normal seed. 
