190 BOTANICAL GAZETTE [SEPTEMBER 
Catalase activity is greater at the end 
of the rest period. It is also greater in the 
than at the beginning 
large mature potatoes 
TABLE IX 
DECREASE IN CATALASE ACTIVITY AFTER STORAGE AT 0° C. 
Spine ob Pack i Teme. cc, O, EVOLVED IN 30-SEC. PERIODS iia 
WHOLE POTATO STORAGE | cropAGE IN 3 MIN. 
1st | 2d 3d | 4th 5th 6th 
ae 
SIG PI < ou: 28 days | 20°C./12.8 |10.5 | 7.5 | 5-5 | 4-3 | 3-8 | 44.4 
Qtg-gM 28 days ot 956 £6.69 | fa | 4.0} 3-1 | 2.6 | 29.3 
bh 
than in the small immature ones. This is true to a much greater 
extent in new potatoes than old ones. 
Mirer-Tuurcav (8) 
found that these same relations exist in regard to respiration. 
TABLE X 
RELATION OF CATALASE ACTIVITY TO AGE AND SIZE OF THE POTATOES 
cc. O, EVOLVED IN 30-SEC, PERIODS 0 
Potato AT WT. oF POTATO |— ee sant, 
1st 2d 3d 4th 
Beginning of rest peri roo gm 16 6 a9 
inni iod .. -3| 14-5 | 13- 
Beginning of rest period ..| 400gm. | 27.3 | 23.8 | 19.9 | 16.9 41°? 
End of rest period Pe nck ws 47 em. | 35.5 | 26.0} 19-1 | 15-9 53° 
End of rest period a a 540 gm 39.0 | 27.5 | 19.1.| 14-5 oo:4 
ces of 
In table XI equal weights of morphologically similar pie 
new and old potatoes of about the same weight were gr? 
und, 
washed into a volumetric flask, and made up to 250 ©¢- = 
water. After thorough shaking, 5 cc. were withdrawn for the 
test, using 5 cc. of hydrogen peroxid as before. 
TABLE XI 
CATALASE ACTIVITY AT BEGINNING AND END OF REST PERIOD pate 
: a ¢ cc, 0, EVOLVED IN 30-SEC. PERIODS Torat cc. 0; 
OTATO AT IN3 MIN. 
: Ist} 2d 3d | 4th | sth 6th aera 
Beginning of rest period 16 as 
i's} 16:0 | 14.8 | 14.6 | 13.5 | 12-9 
End of rest period.......| 21.2 | 20.2 | 18.0 | 16.1 | 14.7 | 13-8 © 
The above facts do not prove a causal relation between catalas? 3 4 
and respiration, but they are highly suggestive, especially " 
