Physically many cats are able to get pregnant as young as only six or seven months old. However, it is better and healthier for pregnancy to occur when they're a little older. Often younger cats are not good mothers; the maternal instinct seems to be better developed when they're one year or older.
Initially, all modern linguistics was historical in orientation. Even the study of modern dialects involved looking at their origins. Ferdinand de Saussure 's distinction between synchronic and diachronic linguistics is fundamental to the present day organization of the discipline.
Scientific history redirects here. For the study of the development of science, see History of science. Historical method comprises the techniques and guidelines by which historians use primary sources and other evidence, including the evidence of archaeology, to research and then to write histories in the form of accounts of the past.