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produced by malaria. The Greek outgrew his city-state, lost his 
faith in religion, and exhausted his strength in a series of suicidal 
civil wars. He practised unnatural vice to an extraordinary extent, 
and this, with other excesses, produced the natural consequences. But 
surely these influences must have been aided in their operation by 
the presence of an insidious foe, which weakened the individual from 
his birth, and left him an easier victim to the disintegrating forces of 
his environment. 
The Roman also outgrew his institutions, and no longer found 
satisfaction in political life. The farms, which had bred a strong- 
race of yeomen, gradually gave place to large grazing estates. Com 
could be imported from abroad more cheaply than it could be grown 
at home, and the farmers crowded into the already-congested 
metropolis. Economic causes, then, as well as political and 
psychological forces, were at work both in Greece and in Italy during 
the period of decline. But the fact remains that the Greeks became 
a race of inefficients, while the Romans of the empire may be roughly 
divided into two classes—a few luxurious debauchees and a host of 
debased and poverty-stricken retainers. 
It is much to be regretted that scientists have paid but little 
attention to the effects of malaria upon national prosperity and 
national character. The economic effects, indeed, are noticed with 
more or less detail by many observers. Celli in his Malaria talks of 
the loss of labour and production caused by the disease, and Clemow 
describes the appalling incapacitation and economic loss which 
accompany its ravages. But its influence upon character has never 
been thoroughly investigated. North, in his fascinating work 
Roman Fever, does say something on the point, but confines himself 
to the general statement that a highly malarious district, if left to 
itself, must contain a population that tends to moral degradation. 
Professor Nieuwenhuis, of Leyden, who has studied the wild tribes 
of Borneo more than any other traveller, writes to tell me t at in 
that island malaria actually has the disintegrating effect which 
assert it had among the Greeks. The results of his investigations 
are to be found in h,s book Qucr durch Borneo. But there certain y 
is room for a book containing an adequate study o t is ques ™ 
both the physical and the psychological standpoints 
preliminary to such work seems to be a historical study of the 
