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verification, by microscopic observation, of the accuracy of the pictorial representations of minute structure in which it abounds. It was issued from the press early in 1849; but, even before its publication, he had begun to feel the effects upon his health, never robust, of the toilsome task he had undertaken, in addition to professional and official engagements, which alone would have been sufficient for the wholesome employment of his time and energies.
Scarcely had his last duties in connection with this work on Anatomy been performed, when, in December, 1848, he was attacked with a severe pleurisy and pericarditis, which brought him into the most imminent danger of life, and from the effects of which he never fully recovered; for though, after a long confinement, he was enabled to go about, and even to resume his professional duties, he was left with great and permanent derangement of his thoracic organs.
The very obvious depression of his left shoulder, and the falling in of the corresponding side of the chest evinced, at a glance, that with the absorption of the pleuritic effusion the lung had not expanded; and the loud murmur, obvious upon auscultation over the heart, proved to his professional friends that this organ had not escaped without serious injury. Notwithstanding, however, the amount of local derangement, his system rallied, and after an absence of some weeks from the city, he returned so much improved in health and strength, that he felt himself authorized to resume his active professional avocations and general previous course of life, though with some abatement of his labors in the fields of original investigation and of authorship.
Could his sense of duty at this period, and the disposition to strong mental activity, which had probably become by habit almost a necessity of his nature, have permitted him to withdraw from all vigorous exertion, and to devote his time for the future rather to quiet enjoyment than to laborious effort, it is not impossible that his life might have been considerably prolonged. Such was the advice of some of his medical friends; but stronger influences impelled him to exertion; and, like most men who feel themselves irresistibly drawn into a certain course of action, he succeeded in reconciling this course not only to his general sense of duty, but even to his views of what was required under the particular circumstances of his health. He was convinced that by active bodily exertion he should
