XXXVI CONTENTS. 



TAGE 



Leiss' New Crystal Refractometer for the Determination of the Refractive Index of 



Large and Microscopically Small Objects (Figs. 43 and 44) 226 



Hilger, Adam — Michelson Echelon Diffraction Grating 228 



Siedentopf, H., & R. Zsigmondy — Visibility of Ultra-Microscopic Particles.. . . 228 



Stringer, E. B. — A New Method of Using the Electric Arc in Photomicrography . . 276 

 Siedentopf, H. — Engelmann's Microspectralphotometer ivith Grating Spectrum 



(Figs. 71-73) ' 359 



Koenigsberger's Microphotometer for the Measurement of Light-Absorption 



(Figs. 74 and 75) 362 



Gordon, J. \V.—Tlie Eelmholtz Theory of the Microscope (Plate VI. Figs. 76-116) 381 

 Rayleigh, Lord — On the Theory of Optical Images, with Special Reference to the 



Microscope (Figs. 117-120) 447 



„ „ On the Theory of Optical Images, with Special Reference to the 



Microscope {Supplementary Paper) 474 



Siedentopf, H. — On the Rendering Visible of Ultra- Microscopic Particles and of 



Ultra-Microscopic Bacteria 573 



Nelson, E. M.— A Micrometric Correction for Minute Objects (Figs. 139-142) .. 579 



„ „ On the " Lag " in Microscopic Visum — (continued) 583 



Bibliography 678 



Drude's Theory of Optics 765 



Conrady, W. A. E. — Numerical Aperture and Rapidity 765 



Remec, B. — Specific Double Refraction of Plant Tissues 765 



Von Kries, J.— Visual Purple 766 



Kime, J. W. — Some Experiments with Actinic Light (Figs. 1-2, plate VIII.) . . .. 766 



Bibliography . . . . 766 



(6) Miscellaneous. 



Glazebrook — Cantor Lectures, 1902 : Glass for Optical Purposes 102 



Molisch's Neiv Freezing Apparatus (Fig. 27) 103 



Bibliography 103 



Nelson, E. M. — Comparison of British and Metrical Measures at the same Tem- 

 perature 364 



Jena Glass 554 



Percival, A. S. — The Microscope 678 



Bibliography 678 



B, Technique. 



Ci) Collecting- Objects, including- Culture Processes. 



Wiley, H. W.— Apparatus for Collecting Samples of Earth for Bacteriological 



Examination 104 



Rivas, D. — A naerobic Cultivation (Figs. 28 and 29) 104 



Czaplewski, E. — Cultivating the Influenza Bacillus 105 



Bibliography 105 



Klein, E. — Method of Defecting the Presence of Bacillus coli communis in Shellfish 229 



Bibliography 229 



Fremlin, H. S. — Anaerobic Plate Cidtures 366 



Grubbs, S. B., & E. Francis— Ring Test for Indol 366 



Bronstein, J., & E. N. Grunblatt — Differentiation of True and False Diphtheria 



Bacilli 366 



Zielleczkey, R. — Differentiation of B. coli and B. typhosus 367 



Rivas, D. — Anaerobic Cultivations 367 



Fitzgerald, Mabel P., & G. Dreyer — Differentiation of B. typhosus and B. coli 367 



Altschuler, E. — Enrichment Method for Typhoid Bacilli 368 



Behrens, W. — Apparatus for Decanting off Culture Fluids (Fig. 137) 557 



Tonzig, C. — New Economical Thermostat of Simple and Light Construction .. .. 678 

 Fretjdenreich, E. v., & others — Milk- Agar as a Medium for the Demonstration of 



the Production of the Proteolytic Enzyme . .. 679 



