THE physical aspects of Palestine with which I propose to deal in this paper will be limited to consideration of the climate and the conditions of health prevailing in the country. In order to understand the nature of the climate of Palestine, it will be necessary first to obtain some idea of the natural features and phenomena which determine a climate. With this knowledge it will be possible to realize the important influences which climate exerts on health.
We have to take into consideration temperature, moisture, atmosphere, wind, soil and electrical conditions, because the combined action of all these, occurring on a localized area of the earth's surface, constitute the climate of a country.
Popularly we speak of warm, temperateand cold climates, and the one which concerns us most just now is, of course, thewarm climate. The main characteristicsfor warm climates are: (1) the extreme differences between the day and night temperatures; (2) the regular recurrence ofrainy and dry seasons; (3) the daily variations in the barometer, and (4) the presence of the malarial poison. But most ofthese phenomena vary with the configuration of the country. The proximity of thesea, the elevation of the land, the interruption of plains by mountain ranges, thepresence of rivers and lakes, the formationof the soil, even to the geological stratahundreds of feet deep, are all concernedin the variations of climate which even onesmall country may exhibit. The vegetation of a country, which is the direct result of climatic conditions, in its turn,profoundly affects the climate.
In Palestine we have present nearly all possible varieties of natural scenery, moun-
* Sixth and last lecture in the series delivered before the London Zionist League.
tain and river, desert and down, sea and lake. This abundance of scenery modifies the climate in different parts of the country to a marked extent, so that its study opens out a wide field to the observer.
This study is obviously a most important one for any society affiliated with the Zionist organization. Indeed, the whole question of acclimatization requires careful thought in any scheme which seeks to remove large numbers of people from one climate to another.
For practical purposes the Jewish people must be regarded geographically asEuropeans. Most authorities consider thatit is not possible for Europeans to becomeacclimatized in tropical countries with anydegree of rapidity. It might be possible,however, after the lapse of many generations, if the original stock were carefullyselected by rejecting all families with anytendency to disease. It is interesting tonote, however, that in the course of historysome great changes have taken place in thisdirection. The Esquimaux once lived inAsia only some 40 degrees north of theEquator; Gypsies are now found everywhere, while Jews apparently thrive underthe most diverse climatic conditions. Butthe process of a race changing its climatic surroundings has been a very slowone, and is not to be compared to a moreor less sudden wholesale emigration.
On the other hand, although the English have become acclimatized at the Cape, in South Australia, New Zealand and some parts of North America, they have not been able to effect this acclimatization in India. It has been said that people who inhabit the Temperate Zone become more easily acclimatized in countries towards the north of their present habitation.
It must be said that on the whole Semi-