Again and again in these pages the hereditary succession of scientific powers has been illustrated. Not the least eminent example is to be found in the case of Sir Joseph Lister, who is the son of Mr. Joseph Jackson Lister, F.R.S., of Upton House, Essex, who in the words of the Rev. J. B. Reade, F.R.S., in his presidential address to the Royal Microscopical Society in 1870, “raised the compound microscope from its primitive and almost useless condition to that of being the most important instrument ever yet bestowed by art upon the investigator of nature.” Mr. J. J. Lister was born in London on January 11, 1786, his parents being members of the Society of Friends. At fourteen years of age he left school to assist his father in the wine trade: but though for many years closely occupied in business, he contrived by early rising and otherwise to supplement his plain school education, and to make himself accomplished in mathematics, as well as generally acquainted with most subjects in literature, science, and art. His predilection for optics was early shown. As a little child with shortsighted eyes, he enjoyed looking through air bubbles in the window-pane, enabling him to see distant objects more clearly. At school he was the only boy who possessed a telescope. He soon became addicted to microscopical study; but it was not till 1824, when he was 38 years old, that he thought of improving the object-glass of the compound microscope, and made suggestions to W. Tulley, the optician, which resulted in the production of a new object-glass much less thick and clumsy, which speedily became the favourite. On January 21st, 1830, he read a paper before the Royal Society “On the Improvement of Compound Microscopes,” announcing the remarkable discovery of the existence of two aplanatic foci in a double achromatic object-glass. This formed a basis for subsequent important improvements. In 1837 he gave to Andrew Ross the construction for a ⅛-inch objective of three compound lenses, by which that maker’s fame was largely increased, and it became the standard form for high power for many years. He also made some notable researches “On the Structure and Functions of Tubular Polypi and Ascidiæ” (Phil. Trans. 1834), and independently came to the same conclusions as Sir George Airy, the late Astronomer-Royal, on the limits of human vision as determined by the nature of light and of the eye; but his paper on this subject was never published, owing to the publication of Sir George Airy’s researches. He survived in vigorous health to see his son Joseph in secure possession of fame, dying on October 24, 1869. His son records[12] that “he was most unselfish, and scrupulously tender of hurting the feelings of others, and extremely generous in the pecuniary support of public philanthropic objects, as well as in secret acts of charity. Though warmly attached to the religious Society of Friends, to which he