“…In the determination of ion accumnlation by .storage tissue, there are two main sources of error, (a) in the method of aeration, (b) in the quantitative procedure itself. The problem of adequate aeration, especially where there is a tendency for tissue .slices to overlap, has evoked some argument (Asprey 1937, Steward and Harrison 1939, Steward and Berry 1943, and Higinbotham and Hanson 1955. Where forced aeration is employed, spraying of the solution is sometimes encountered.…”