1913] ECKERSON—AFTER-RIPENING 205 
in order of the depth of color of the reaction for peroxidase and 
oxidase. 
TABLE IV 
ENZYMES IN HYPOCOTYLS OF CRATAEGUS DUROBRIVENSIS 
Catalase Peroxidase Oxidase 
Air-dry at 5° C. 14 days....... Very little Very pale ° 
a ce ce a Little | Light blue ° 
Pe OE TIE oe se, Light blue ° 
ag 00 BERG os x Slightly darker ° 
mee babyre. ec oe: = Slightly darker ? 
Wel TO DOIC eee iba a ea x Darker race 
MOC. 1 x Darker Trace 
Di YGoe acktic: 2... 2G: x Like after- Dark blue 
ripen 
After-ripened go days at 5°C.. = Dark blue Dark blue 
so sorte snl x Deep blue Darker 
In 14 days embryos treated with N/rooo acetic acid attain an 
enzyme reaction equal to that of the untreated embryo after 90 
days’ after-ripening. Both N/3400 HCl and N/7o butyric show 
a great increase in enzymes over the control. 
The acidity was determined in several cases. The testas and 
embryos were always carefully washed in boiled distilled water to 
prevent any trace of external acid vitiating the results. The accom- 
panying table (V) gives the results of one series. 
TABLE V 
ACIDITY IN EMBRYOS OF CRATAEGUS DUROBRIVENSIS 
Hypocoryts CoryLEDONs 
IN ACID OVER NIGHT N/20 KOH N/20 KOH 
Grams |N/20KOH)" Grams N/: ——— ce. per 
cc. : gram 
a A 
OME, iis SI fe sae 0.37 
é basic 
N/7o butyric 16 hours. ... 0.0184 | Neutral| 0.00 | 0.3544 | 0.16 0.45 
a 
SE pean Rang aa! sn, 0.009 0.01 T.1t' | 6.3198 |. 6.05 2.06 
ee ene ane 0.0119 | 0.02 1.68 | 0.2420] 0.40 1.65 
After seeds have been in N/7o butyric acid 16 hours, the outer 
cells of the cortex of the hypocotyl give an acid reaction with Dahlia 
