ELEMENTS OF BOTANICAL MICROTECHNIQUE BY JOHN E. SASS, PREFACE Permanent slides for microscopic study are indispensable in the teaching of a basic course in botany and in some specialized advanced fields. In some advanced courses the students prefer many of the slides as a minor aspect of the course, but in elementary courses the slides usually are furnished. In the latter case the slides are either purchased from commercial sources or made in the departmental laboratory. Biological supply houses can furnish excellent slides of the subjects commonly used in elementary teaching, but the quality is likely to be variable, especially from concerns in which there is frequent turnover of the laboratory staff. Jobbing houses that purchase slides from constantly changing sources may also furnish disappointing slides at times. The more reputable concerns , however, try earnestly to meet the specifications of critical and reasonable purchasers. The relative merits of making slides and of...