284 THE AMERICAN MONTHLY. [December. 



time^the treatise is in the hands of the student its technique is anti- 

 quated. This fault cannot be attributed to the book before us. It is 

 up to date, and the sections devoted to homogeneous immersion objec- 

 tives, the sub-stage illuminator, the camera lucida, the micro-spectro- 

 scope, and the mici-o-polariscope will be especially welcome to workers. 

 The suggestions are sententious, but helpful. The typographical work 

 is well done, and altogether it is one of those books that the student 

 and worker in microscopy cannot afford to be without. We submit 

 that a book which is likely to be in such constant use should never be 

 purchased in paper covers. F. B. 



SUBSCRIBERS' NOTICES. 



[These notices will be given six insertions in this column at 25 cents per line or fraction thereof.] 



WANTED. — A Bulloch Professional Stand. Address, stating price. — 



HENRY C. WELLS, 151 Broadway, New York City. 



WANTED.— Vol. VII, No. 2 (B'eb., 1886), of American Monthly Microscopical Journal. 



A. G. YOUNG, State House, Augusta, Me. 



WANTED. — Diatom material from America, Australia, and Asia in exchange for fossil and recent 

 material from Denmark. 



CHR. MICHELSEN, 33 Nedergade, Odense, Denmark. 



FOR EXCHANGE. — Slides of diatoms from peat bogs in Boston, Mass. 



F. F. FORBES, Brookline, Mass. 



WANTED TO PURCHASE. — Histological slides from normal tissues of mammals, prepared with 

 a view to show the size of the " cells," in cases where the age of the animal-subject is definitely known, 

 as bearing on the question of a supposed diminution in the size of cells in aging organisms, correspond- 

 ing to a similar decrease, reported by Balbiani and Maupas in aged unicellular life. Address, 



C. A. STEPHENS' LABORATORY, Norway Lake, Maine. 



WANTED. — Diatomaceous material of good quality, fossil and recent. I offer diatom slides or 

 photo-micrographs in exchange. 



D. B. WARD, Poughkeepsie, N. Y. 



OFFERED. — Diatomaceous Earth from Utah (Desert) for Histological Mounts. 



PROF. ORSON HOWARD, Salt Lake City, Utah. 



WANTED. — Any works on Microscopy not already in my Library. 



H. M. WHELPLEY, F. R. M. S., St. Louis, Mo. 



First-class Histological Slides for other good mounts ; Histological and Pathological material cut on 

 shares. S. G. SHANKS, M. D., 547 Clinton Ave., Albany, N. Y. 



FOR SALE OR EXCHANGE. — Mosquitoes, male and female. Price 75 cents each. Will ex- 

 change only for first-class mounts. E. W. SHARP, 2800 Richmond St., Philadelphia, Pa. 



A 1^5 MICROSCOPE. — Made on proper scientific principles. Magnifies 100 diameters or 10,000 

 times. For other interesting articlts send for list of Popular Scientific Specialties. 



G. S. WOOLMAN, 116 Fulton St., New York. 



SPECIAL BARGAIN in histological slides. 



WM. N. BEGGS, M. D., 2207 Sidney St., St. Louis, Mo. 



FOR SALE OR EXCHANGE. — Photo-micrographs of P. angulatura taken through Spencer's 

 ("5 H. I., 2400 diameters. Also photo-micrographs of bacteria, diatoms, etc.. 25 cents each. Will ex- 

 hange for well-mounted slides. Dr. J. E. BAKER, Wyoming, Ohio. 



TO MICROSCOPISTS. — After July i the price of my well-known slides will be the uniform one of 

 50C. each, fc.oo per dozen. Send 2c. stamp for catalogue and 50c. for slide of Podura scales, test, or 

 other diatoms, or of miscellaneous objects. Thum's " Oh, My !" slides of arranged diatoms, gorgeous 

 butterfly scales, etc., at lowest rates. 



M. A. BOOTH, F. R. M. S., Longmeadow, Mass. 



FOR SALE. — Spencer's i-in. 40° objective; first-class 'series ; new; and Spencer's jj in 113° B. 

 A. homo. imm. Professional series; has been used, but is in perfect order. Reason for selling, bad 

 health and failing eyesight. 



THOS. H. URQUART, M. D., Hastings, Neb. 



