Scope and Contents This Brevet Lieutenent Colonel, assistant surgeon in the U. S. Army, prepared photo-micrographs of histological preparations by an improved method of using sunlight in 1871. Later he prepared photo-micrographs mounted on cards for the International Exposition of Philadelphia of 1876. The latter was apparently an exhibition put up by the War Department. Our collection, while not complete, illustrates various categories: (1) Diatoms, 20 plates; (2) Insect scales, mosquitos, gnats, 10 plates;...

Overview Joseph Mellick Leidy (1823-1891), one of the great American scientists of the 19th century, possessed a vast knowledge of the natural world. Best known as the Father of American vertebrate paleontology, he also pioneered the fields of parasitology and protozoology, and was the preeminent anatomist of his time. He was also an influential teacher of natural history and an expert in areas as diverse as entomology, geology and pathology. The Joseph Leidy Correspondence collection contains...