“…The procedure for the barrier penetration assays included controlling the motivation of the test subjects and training the test subjects to better ensure each test subject would perform consistently (Stolurow, 1948). Previous testing achieved motivation control by limiting the availability of maintenance food through food rationing and fasting or by maintaining test subjects at 70% of their normal body weight to ensure proper motivation (Bellack and DeWitt, 1950;Bendig and Stolurow, 1952;Welch, 1954;Glahn and LaVoie, 1983). In addition, test subjects were subjected to intensive training programs to eliminate animals unwilling to perform the required task (Welch, 1954;Glahn and LaVoie, 1983).…”