9. Similarly, the relation of the seasons to health was 
carefully noticed. The year was divided into six seasons, 
namely, the cold, the spring, the hot, the rainy, the moist, 
and again the cold ; so that the first-named included our 
months of January and February, the last-named our No- 
vember and December. As to instructions with regard to 
what would now be designated personal hygiene in each of 
these seasons, I select one, namely, the hot, including our 
months of May and June. Chakrata said : “ Use cool foods, 
and food prepared with ghee (clarified butter) ; drink sherbets; 
use broths of wild animals and birds ; eat rice with milk and 
ghee ; little wine is to be used, and always mixed with much 
water; do not take much exercise ; sleep during the day in a 
cool room ; at night in the upper rooms ; use the hand-punkah 
sprinkled with sandal-wood and water.” The date when these 
instructions were first issued is variously given as the sixth to 
ninth ceutury before the Christian era. And yet there are 
those who say, and perhaps believe, that not until the nine- 
teenth century of our era — that is, twenty-five centuries after 
the time of Chakrata — was hygiene, as a practical thing, 
evolved from man's “ inner consciousness.” But time pre- 
vents the further consideration of this portion of our subject. 
10. Of all the influences to which plants are exposed, 
climate is the most important; it sets absolute limits to 
species.* Plants have been referredf to divisions in classifica- 
tion according to their relation to climatic conditions — namely, 
1, Macrotherms, those of inter-tropical regions ; 2, Meso- 
therms, those of sub-tropical and warm, temperate zones; 3, 
Meiotherms, or those inhabiting cool, temperate zones ; 4, 
Microtherms, or those inhabiting alpine or arctic regions. 
With reference to the local characters of climates, another 
method of classification has been adopted, as Xerophiles, or 
such as pertain to very dry climates ; Hygrophiles, or those 
which abound in abundance of moisture ; and Noterophiles, or 
those intermediate in character. Structural conditions of 
plants also correspond to the character of climate and soil in 
which they exist — monocotyledones in hot climates, dicotol} 7 - 
dones in cold. Those deep-rooted for extremes of heat and 
cold ; those with shallow roots for equable climates. J The 
character of foliage, alike in type and in continuance, differs 
in unison with differences in climate. 
* Changes of climate must also have their influence upon the migration 
of plants. A region, when its climate was different, may have been a high 
road for migration for plants, although it is now impassable. 
+ By Decandolh. 
$ JH enfrey’s Elementary Course of Botany, pp. 660, 661. 
