ROLE OF DEPOPULATION—-REGNAULT. 597 
The Kingdom of Spain at present presents the same aspect. Its 
capital rises in the midst of vast solitudes. Some large proprietors 
share in the deserts of Castilla and the plains of Andalusia, which 
continue to be ravaged by their flocks of sheep and goats. 
Devastating wars, unjust laws, low morale, depopulation following 
upon a low birth rate or intense emigration—all these factors, which 
are often cited by historians to explain decadence, are but passing 
causes. As long as the richness of the soil is not destroyed prosperity 
can rapidly return, and the instances of these fluctuations in the great- 
ness of peoples are not rare in history. 
But reforestation, restoration of vegetal earth on a denuded soil, 
turning torrents into peaceful watercourses, the drainage and sani- 
tation of the swamps—these are works which require centuries of 
constant and devoted labor, the sacrifice of numerous generations. 
Thus Greece, Italy, and Spain continually suffer from those evils which 
a single improvident generation could cause, but which are so difficult 
to combat. 
At present we are better equipped against those evils. In the first 
place, we have grasped their seriousness, which formerly was not 
understood. Governments devote large sums to reforestation, and 
patriotic associations lease the pastures and conserve them by limit- 
ing the number of cattle. In this way Sologne and the Landes (in 
France), where in the eighteenth century no tree rose from the ground, 
“were reforested; in Sologne the sylviculturist preserved the seedlings 
from the voraciousness of the hares by means of wire fences; in 
Landes they built up the soil, so that the water which rotted the 
grains would run off. 
Malaria is fought by the administration of quinine, by pouring 
petroleum on the swamps, by barricading doors and windows with 
wire screens, by the multiplication of dytiscid insects, fishes, birds, 
and bats, all of which are great destroyers of the mosquito. 
Finally, the depopulation which prevails not only in France but in 
all western Europe no longer results in turning agricultural lands into 
pastures, thanks to the agricultural implements, which lessen the 
number of laborers, and to the railways, which rapidly transport the 
workingmen in harvest time. 
This is not to say that depopulation, when pushed to an extreme, 
is not evil. Thus in certain districts in France with a low birth rate 
fertile fields are neglected, and the mediocre lands, whose yield would 
not compensate for the expense involved for labor and in bringing 
harvesting machines from a distance, are abandoned. But it is cer- 
tain that the means at present at our disposal make it possible for a 
country to pass through a crisis of depopulation without quickly 
becoming, as was formerly the case, the victim of complete ruin. 
