While German science was involved in the enervating network of æsthetic speculations, his own energy and happy skill enlisted Humboldt in wider spheres of healthy activity for its salvation. Even in our fast-living age, it is hard to conceive that only two years after he had been enjoying in the Saal Valley those visions, short indeed, but in a certain sense, like a young love, decisive as to his life, he was observing in Cumana the first periodical shower of stars, and discovering the electric folds in the brain of the torpedo-eel; was exploring the caves of Caripe resonant with the cries of the guachero; was threading in a pirogue, environed with alligators, the stream-net of the Rio Negro and the Cassiquiare between the Orinoco and the Amazon; and in Esmeralda, on the upper Orinoco, was observing the concoction by the natives of the weird arrow-poison, curare, which owes its name to him. Nothing was wanting to raise the fantastic charm of these journeys, from which, nevertheless, Humboldt brought back a greater sum of acute, distinct observations in every conceivable field of science, in geography and anthropology, than any single observer ever collected either before him or after him. No! The world will "never see his like" in comprehensive, restless activity, combined with lofty thought; in dauntless venture for ideas, with the wisest saving of means and strength; in soaring height of feeling, the expression of which frequently, in view of the sad contentions of mankind or of the horrors of slavery, for instance, has an elegiac tone, as in a similar way a delicate haze adorns his sketches of the giant heights of the Cordilleras.
It is essential to the success of a scientific journey, first of all, that the traveler return. But, besides threatening him with physical dangers, which Humboldt's apparently not very strong body resisted wonderfully, long journeys in wild regions have other inconvenient consequences. Habituation to perfect freedom in solitude, to constant change and external stimulation, even excitement, the diversion from accustomed literary occupations, render it very hard for travelers to feel themselves at home again, to give themselves up to the complicated demands of cultivated society, and to be satisfied to make the most of the treasures they have brought with them. They seem to prefer to such allegiance a return to the wilderness, so that it is said of African travelers that the greatest danger that threatens them is the unconquerable propensity, when they have once escaped the perils of the journey, to try them again. Thus it was with Humboldt's fellow-traveler, Bonpland, who was drawn back to South America, where it was his fate, not to perish, but to be lost to science, a prisoner to Dr. Francia. He left to Humboldt, in whom no trace of such weakness could be found, the fruit of many of their common labors.
Humboldt had lived in Paris before his journey. He now permanently fixed his place of labor there, as the only place where he could perfect the literary undertakings he had planned; and as with curious