Mendelian Heredity
57 objects illustrate this topic:

Page: of 6 
"A Diagram of Heredity," by Francis Galton, Nature (vol. 57:1474) (#2010)
American Eugenics Society exhibit at Sesquicentennial Exposition, Philadelphia ("Mendel's theater," center; guinea pig coat color, right) (#1565)
"Another Wooly-Hair Mutation in Man," by C.Ph. Schokking, Journal of Heredity (vol. 25), multiple pages (#2312)
Carl Correns notes on Mendel's analysis of dominant and recessive charateristics in peas (4/16/1896) (#2261)
"Case I: 2 homozygous brown eyed parents will have 100% homozygous brown eyed children" (#962)
"Case II: homozygous brown eyed parent and heterozygous brown eyed parent will have..." (#987)
"Case III: one homozygous brown eyed parent and one homozygous blue eyed parent will have 100% heterozygous brown eyed children" (#988)
"Case IV: two heterozygous brown eyed parents will have 25% homozgyous brown eyed, 50% heterozygous brown eyed and 25% homozygous blue eyed children" (#989)
Charles Davenport letter to Francis Galton, requesting a reference for his proposal for the Station for Experimental Evolution (10/14/1902) (#2093)
Charles Davenport letter to Karl Pearson, defending roles of mutation and environment in evolution in paper rejected by Biometrika (6/5/1903), multiple pages (#2121)
Charles Davenport letter to Karl Pearson, emphasizing his break with Bateson and De Vries on environmentally induced mutations (7/7/1903), multiple pages (#2127)