The effect of instructional analogy training on the level of immediate, as well as 14-day delay, comprehension of tangible and intangible physiological concepts was investigated. Ninety-four college-aged subjects were given training either with or without instructional analogies over five tangible and five intangible advanced physiological concepts. Results showed significantly higher scores of comprehension, both immediately and after the delayed period, for those subjects who had received the analogies. Moreover, subjects receiving analogies reported higher perceived levels of lesson enjoyment. Results are discussed in terms of the prescriptive use of analogies within instructional materials and future research possibilities. Two figures are appended. (52 references) (Author/BBM)