Editorial note — Chapter XV · Experimental Work in Physiology.

Note. For detailed suggestions in regard to the manipulation and use of the microscope the student is referred to any of the standard works on the subject. The catalogues of scientific-instrument makers of our larger cities generally furnish a list of the requisite materials or handbooks which describe the use of the various microscopes of standard make. The author is indebted to Bergen’s Elements of Botany for the following information concerning the different firms which deal in microscopes. “Several of the German makers furnish excellent instruments for use in such a course as that here outlined. The author is most familar with the Leitz microscopes, which are furnished by Wm. Krafft, 411 West 59th St., New York city, or by the Franklin Educational Co., 15 and 17 Harcourt St., Boston. The Leitz Stand, No. IV., can be furnished duty free (for schools only), with objectives 1, 3, and 5, eye-pieces I. and III., for $24.50. If several instruments are being provided, it would be well to have part of them equipped with objectives 3 and 7, and eye-pieces I. and III. “The American manufacturers, Bausch & Lomb Optical Company, Rochester, N.Y., and No. 130 Fulton St., New York city, have this year produced a microscope of the Continental type which is especially designed to meet the requirements of the secondary schools for an instrument with rack and pinion coarse adjustment and serviceable fine adjustment, at a low price. They furnish this new stand, ‘AAB,’ to schools and teachers at ‘duty-free’ rates, the prices being for the stand with two eye-pieces (any desired power), ⅔-inch and ¼-inch objectives, $25.60, or with 2-inch, ⅔-inch, and ¼-inch objectives, and two eye-pieces, $29.20. Stand ‘A,’ the same stand as the ‘AAB,’ without joint and with sliding tube coarse adjustment (as in the Leitz Stand IV.), and with three eye-pieces and ⅔-inch and ¼-inch objectives, is furnished for $20.40. Stand ‘A,’ with two eye-pieces, ⅔-inch and ⅙-inch objectives, $20.40.”