Note 37 — Chapter II · Contamination of Instincts in Primitive Technology

These improved races are commonly, if not always, a product of hybridisation, though it is conceivable that such a race might arise as a “sport,” a Mendelian mutant. To establish such a race or “composite pure line” of hybrids and to propagate and improve it in the course of further breeding demands a degree of patient attention and consistent aim.