Coeval with these great and rapidly advancing changes, we can already discern some of those evils too commonly attendant on increased wealth, luxury, and intelligence: anxieties, excesses, passions are largely multiplied, and the medical observer cannot fail to distinguish, amongst certain ranks of the hitherto contented and indolent Brazilians, unequivocal traces of that premature ‘wear and tear,’ so strongly and painfully characteristic of high civilization. It now only remains that we should briefly notice the extent to which certain great classes of disease have been influenced and modified by the preceding moral and physical agencies. This is chiefly manifested in the increasing number of cerebral and pulmonary maladies, and diseases of the heart and great vessels. Insanity has also become much more frequent than formerly, though still rare as compared with other nations; which, indeed, might be inferred from the fact that the ‘Mad Doctor’ is a species of the profession as yet unknown to Brazil. Suppurative inflammation of the liver has increased, but of all the acute diseases, fevers have been the most profoundly modified; they partake much more generally of the low, or asthenic character, and assume the remittent and continued type, and are greatly more fatal in their results than formerly. This naturally brings us to the important question of the ‘yellow fever,’ which for the last four or five years has ravaged the great maritime cities of the empire. Its origin has given rise to the most conflicting views, amongst the best observers;—for example, Dr. Pennell of Rio, and Dr. Paterson of Bahia, both men of undoubted talent and great professional experience, entertain precisely opposite opinions; the former contending for the indigenous, the latter for the foreign origin of the disease; and both offer cogent arguments and striking facts in support of these opposite conclusions. The scope of this work does not admit of medical discussion, yet as the facts observed by Dr. Pennell are highly important, and as his conclusions entirely coincide with our own experience, we will condense them here. Dr. Pennell states that for some years the fevers of the country had been clearly changing their character, that the genuine remittent had been little seen for three years; that it was replaced in 1847, ’48, and ’49, by a fever of its own class, popularly known as the ‘polka fever,’ but in reality a remittent; and that this fever was, in its turn, superseded by the ‘yellow fever,’ a disease with similar features: he adds the following words, ‘coincident with these and other changes in the diseases of Brazil, the climate, in its broad features, has altered strangely: thunder-storms, formerly of daily occurrence, at a certain hour, during the summer, are now but seldom heard, &c.,’ and concludes, ‘that bilious remittent and yellow fever are essentially the same disease,’—a proposition entirely in accordance with my own experience in Brazil and other countries. The abettors of the foreign origin of yellow fever insist that it was imported by a certain ship from New Orleans into Bahia, and thence diffused throughout the empire; whilst the facts adduced by Dr. Pennell go far to establish, as already stated, its indigenous parentage. In support of this opinion we have the strong additional fact that, for the last forty years, there has existed uncontrolled by any efficient quarantine laws, an extensive intercourse with the United States, Africa, and the West Indies, the very hot-beds of yellow fever; and yet, up to 1849, Brazil remained perfectly healthy. Can we then in reason believe, if the disease be deemed really importable, that the maritime cities of Brazil could, under such circumstances, have escaped infection for a period of forty years? It is moreover important to know that several of the older writers, as Rocha Pita in 1666, Père Labat in 1686, Fereira da Rosa in 1694, have recorded the appearance of epidemics closely resembling the yellow fever, and which, after persisting for some years and desolating several of the large cities on the coast, finally passed away. Some seventy years ago, the capital itself was visited by an epidemic fever no less fatal to the population than that from which it now suffers.