“…Andervont and Shimkin pioneered with the model involving the development of lung tumors in specific sensitive strains of mice, especially the A/Heston strain and related strains like A/J (1,12 Shay discovered, and Huggins extended, the finding that polycyclic hydrocarbons rapidly induced cancer in the mammary gland of young female random-bred Wistar rats and, to a greater degree, in Sprague-Dawley rats (1,4). With powerful carcinogens, especially select polycyclic hydrocarbons, arylamines, or nitrosoureas, a positive result is obtained in less than nine months.…”