Page:The Olive Its Culture in Theory and Practice.djvu/162

132 developed. In truth it is not found before November, the season when the oily material is formed in notable quantity, and on the other hand it is met with in December, January and even in February an epoch in which the vital functions are at the minimum of activity.

The conclusion from this is, that the sugar existing in the leaves has no part in the formation of the fatty material, and it is not to be considered other than as a product of metamorphosis of other hydrates of carbon of secondary importance for oily plants.

The time in which to harvest the olive varies according to climate and the product desired. It may depend absolutely on climate, as the maturity of the olive is hastened and more oil is obtained where the temperature is high and vegetation has the advantage of a vivid light.

So the olive matures earlier and carries more oil at the extreme south of its zone, but the oil is fatty, high-colored and only useful in manufactures or as an illuminant, being utterly useless for food. For the latter purpose it should carry little fat or color.

Hence it follows that the northern part of the olive zone produces the finest oils at full maturity, whilst towards the south to secure the same result it is necessary to anticipate and to harvest while the berries are still yellowish or just turning purple.

So in northern Italy and southern France a fine table oil is obtained from olives that are black and fully matured, and the famous white oil is made by allowing the berries to become over-ripe and deferring the harvest till March, April and even May.

On the other hand, in southern Italy and Sicily a fine oil is obtained by early harvesting, mature berries giving an oil that is exceedingly gross, dense, highly colored and of a disgusting taste. So when seeking to produce an oil for table use, the effect of the climate may be modified to a certain degree.