When a textbook is "short," one wonders immediately what was shortened. A comparison with recent editions of Harrison's and Cecil and Loeb's texts reveals several obvious shortenings: weight (0.79 kg against 3.91 kg and 4.4 kg); pages (573 against 1,947 and 1,665); estimated words (250,000 against 1,417,000 and 1,378,000); and authors (7 against 116 and 164).
A more important issue, however, is what was deleted and how was the remaining material shortened or lengthened. For examining these questions, a ratio was obtained by dividing the number of words on a topic in the "short" textbook by the average words in corresponding sections of the two long texts (Harrison, and Cecil and Loeb). The overall ratio for total words is about 0.178, that is, the long books are 5.62 times longer than the short text. A topic ratio less than 0.1 is taken to indicate a relative reduction in coverage and