The cytogeneticist John Belling (1866-1933) developed the iron-acetocarmine staining technique, which facilitated detailed study of chromosomal structures. In his work with Arthur F. Blakeslee at Cold Spring Harbor on Datura (1920-1927) and at the University of California, Berkeley (1928-1933) on lilies, hyacinths, and other plants, Belling made accurate estimates of chromosomal numbers, helped to demonstrate the interchange of segments between non-homologous chromosomes, and proposed that the chromomeres (small condensations of stain that appeared along the length of chromosomes) represented individual, physical genes. Although he was a gifted technician and insightful cytologist, his career was hampered by mental instability and curtailed by frequent hospitalizations before his sudden death in 1933. The Belling Collection consists of four photograph albums, 38 glass slides and approximately 75 glass negatives and positive prints of chromosome preparations made by Belling, primarily during the years at Berkeley, along with an annotated bibliographic card file. The images in the albums are fully identified, but most of the glass slides are not.

Hans Ris (1914-2004) was an American cytologist and pioneer electron microscopist. His studies of chromosome structure revealed the importance of non-histone proteins and he was one of the first to recognize that blue-green algae was a special type of bacteria. He coined the term genophore for prokaryote DNA. Elected to the National Academy of Sciences in 1974, he was a founder of the American Society for Cell Biology. The Hans Ris papers consist of correspondence, research notes, published and unpublished works by Ris and others, related to the latter part of his career. The bulk of the collection contains micrographs from the High Voltage Electron Microscopy (HVEM).

This collection includes correspondence, manuscripts (lectures and articles), research grant material, research data, and participation in organizations, such as, the American Society of Naturalists (President, 1968), Genetics Society of America (President, 1963), and the National Research Council. Of particular note, are the detailed data related to Drosophila eye pigment, and human chromosomes.

Though the Miscellaneous Manuscripts collection is composed of items that do not fall readily into any other existing collection, the two dominant intellectual areas represented in the collection are Early American History and History of Science.