Walther Flemming, Eduard Strasburger, Edouard van Beneden, and others elucidated the essential facts of cell division and stressed the importance of the qualitative and quantitative equality of chromosome distribution to daughter cells.
1881 James A Garfield becomes twentieth president of the United States.

Six months after taking office, Garfield becomes the second US President to be assassinated.

Chester A. Arthur becomes twenty-first president of the United States.

  Eduard Strasburger coins the terms CYTOPLASM and NUCLEOPLASM.

W. Flemming discovers lampbrush chromosomes and coins the term MITOSIS.

  Pierre Émile Duclaux introduces the custom of designating an enzyme by the by the name of the substrate on which its action was first reported and adding the suffix "- ase".

Edouard van Beneden announced the principles of genetic continuity of chromosomes and reported the occurrence of chromosome reduction at germ cell formation. The sperm and egg are haploid and fertilization restores the diploid chromosome number.

Wilhelm Roux offers a possible explanation for the function of mitosis.

A. Weismann points out the distinction in animals between the somatic cell line and the germ cells, stressing that only changes in germ cells are transmitted to further generations.

  Walther Flemming, Eduard Strasburger and Edouard van Beneden demonstrate that chromosome doubling occurs by a process of longitudinal splitting. Strasburger describes and names the PROPHASE, METAPHASE, and ANAPHASEstages of chromosomal division.
  Identification of the cell nucleus as the basis for inheritance was independently reported by Oscar Hertwig, Eduard Strasburger, Albrecht von Kölliker, and August Weismann.
  Karl Rabl theorized the individuality of chromosomes in all stages of the cell cycle.

Walther Flemming observed sister chromatids passing to opposite poles of the cell during mitosis.

August Weismann formulated the germ plasm theory which held that the germ plasm was separate from the somatoplasm and was continuous from generation to generation.

1885 Grover Cleveland becomes twenty-second president of the United States.
  Francis Galton devised a new useful statistical tool, the correlation table.
1886 Daimler produces his first car.
  August Weismann elaborated an all-encompassing theory of chromosome behavior during cell division and fertilization and predicted the occurrence of a reduction division (meiosis) in all sexual organisms.

Wilhelm Roux put forth the suggestion that the linearly arranged qualities of the chromosomes were equally transmitted to both daughter cells at meiosis.

Edouard van Beneden demonstrated chromosome reduction in gamete maturation, thereby confirming August Weismann's predictions.

  Theodor Boveri verifies August Weismann's predictions of chromosome reduction by direct observation in Ascaris.

Heinrich Wilhelm Gottfried Waldeyer names the CHROMOSOME.

  Francis Galton publishes Natural Inheritance. In it he describes the quantitative measurement of metric traits in populations. He thus founds biometry and the statistical study of variation. Ultimately, he formulates the Law of Ancestral Inheritance, a statistical description of the relative contributions to heredity made by one's ancestors.
1889 Benjamin Harrison becomes twenty-third president of the United States.