The rainy seasons are healthier for the natives than the cold
seasons; and the explorer is often urged to take advantage of
them. He must, however, consult local experience. Whilst
ascending rivers in November, for instance, he may find the many
feet of flood a boon or a bane, and his marching journeys are
nearly sure to end in ulcerated feet, as was the case with poor
Dr. Livingstone. The rains drench the country till the latter end
of December, when the Nanga or "little dries" set in for two
months. The latter also are not unbroken by storms and showers,
and they end with tornadoes, which this year (1862) have been
unusually frequent and violent. Thus we may distribute the twelve
months into six of rains, vernal and autumnal, and six of dry
weather, aestival and hibernal: the following table will show the
sub-sections:--

Early December to early February, the "little dries;" February to
early April, the "former," early or spring rains; May to early
June, the variable weather; June to early September, the Cacimbo,
Enomo, long or middle dries; September to early December, the
"latter rains."

Under such media the disease, par excellence, of the Gaboon is
the paroxysm which is variously called Coast, African, Guinea,
and Bullom fever. Dr. Ford, who has written a useful treatise
upon the subject,[FN#7] finds hebdomadal periodicity in the
attacks, and lays great stress upon this point of
chronothermalism. He recognizes the normal stages, preparatory,
invasional, reactionary, and resolutionary. Like Drs. Livingstone
and Hutchinson, he holds fever and quinine "incompatibles," and
he highly approves of the prophylactic adhibition of chinchona