These elements have resulted in theories connecting the two, and the notion has had some influence, appearing in school books for children from the 19th century and into the 20th century.
これらの要素は2つを繋ぐ学説を生じさせ、そしてこの概念は19世紀から20世紀の子供向けの教科書に登場し影響を与えた。