Germination of Helianthus annuus . II. 899 
In the ether extract of the hypocotyls and roots, however, entirely 
different results are obtained from that of the cotyledons. At Stage I 
the iodine number has fallen to 1177. It stays constant during the next 
stage and then falls rapidly, amounting to only 43-3 in the last stage of the 
seedling. This indicates that the free and combined fatty acids of the ether 
extract of the hypocotyls and roots become saturated to a considerable 
extent at the beginning of germination, and that this saturation becomes 
more and more complete as germination progresses. 
The Acetyl Value. The acetyl value of an oil gives the number of 
milligrams of caustic potash required to neutralize the acetic acid that is 
set free when one gramme of the acetylated oil is saponified. The acetyl 
value is really a measure of the amount of the hydroxyl groups which an 
oil contains. 
The acetyl value of the ether extract of the seed is 40-1. The value 
remains practically constant for the oily material of the cotyledons during 
all stages of the seedling. The slight decrease in the acetyl value at the 
last stages comes within the limit of error of the process. It seems, then, 
that there is no increase in the amount of the hydroxyl groups of the ether 
extract of the cotyledons during any stage of germination. 
The acetyl value of the ether extract of the roots and hypocotyls was 
determined for the first three stages of the seedling. The value amounts 
to 71-2, 114-0, and 95*1 for each of the respective stages. The results are 
thus much higher than those obtained for the ether extract of the cotyledons. 
The amount of soluble glycerides present is far too small to account for 
this high value. It seems, then, that the ether extract of the roots and 
hypocotyls has a much larger amount of hydroxyl groups than that of the 
cotyledons. 
General Considerations. 
The Oily Material of the Cotyledons . The saponification value, total 
insoluble acids, total soluble acids, and iodine number of both the ether 
extract and neutral oil of the cotyledons of the seedling remain constant 
up to the time when seven-eighths of the original oily reserve present in 
the seed has disappeared. A marked change in these values takes place 
only in the last stage examined, when only 5-3 per cent, of the original 
oil remains in the cotyledons. The change in values for the above constants 
indicates that the oily material at that stage consists to a small extent of 
glycerides and free fatty acids of lower molecular weight than those com- 
posing the original oily reserve of the seed. The change in the iodine 
number indicates that both the free fatty acids and glycerides are becoming 
partially saturated, probably by the addition of oxygen. 
The acetyl value of the ether extract remains constant for all stages of 
the seedling, and indications are thus given that the amount of hydroxyl 
3 N 2 
