CLARK, Henry James, naturalist, born in Easton, Massachusetts, 22 June, 1826 ; died in Amherst, Massachusetts, 1 July, 1873. He was graduated at the University of New York in 1848, after which he taught for some time in White Plains, New York Here he developed a taste for botany, and entered into a correspondence with Prof. Asa Gray, which presently led to his becoming a student at the Botanic garden, Cambridge, in 1850, while at the same time he supported himself by teaching in the academy in Westfield, Massachusetts. Soon afterward he became a student under Louis Agassiz, and was graduated at Lawrence scientific school of Harvard in 1854. He then became private assistant to Agassiz, who pronounced him "the most skillful microscopist in the country," and was associated with him from 1856 till 1863 in the preparation of the anatomical and era-bryologieal portions of the " Contributions to the Natural History of the United States." In June, 1860, he was appointed adjunct professor of zoology in Lawrence scientific school, and in 1861 gave a course of lectures on histology at the Mu seam of comparative zoo1ogy. An unfortunate disagreement with Prof. Agassiz led to his severing his relations with the museum in 1863, and during the following year he delivered twelve lectures at the Lowell institute with the title of "Mind in Nature." In 1866 he was appointed professor of botany, zoology, and geology in the Agricultural College of Pennsylvania, where he remained until 1869. He then became professor of natural history at the University of Kentucky, Lexington, and in 1872 was elected professor of veterinary science in Massachusetts agricultural College at Amherst. Prof. Clark was a member of most of the learned societies in this country, and had been elected to the National academy of sciences. Besides valuable contributions on scientific subjects to "Proceedings of the American Academy of Sciences and Arts," of the "Boston Society of Natural History," " American Journal of Science," and "Smithsonian Contributions," he was the author of "A Claim for Scientific Property" (Cambridge, 1863), and "Mind in Nature, or the Origin of Life, and the Mode of Development of Animals" (New York, 1865). For a full list of his scientific papers and works, see Prof. Asa S. Packard, Jr.'s " Memoir of Henry James Clark" in the " Biographical Memoirs of the National Academy of Sciences" (Washington, 1877).