TA.BUe OR COIVTEINTS. 



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Official Directory i 



Constitution of the Academy 3 



Members of the Academy 7 



Proceedings of the Fifteenth Annual Session 11 



Presidents address, by W. H. Norton 17 



A Review of the Tettigonidae of North America north of Mexico, by E. D. Ball 35 



The Morphology and Function of the Amphibian Ear, bvH. W. Norris 76 



A Combination of Chromic Acid, Acetic Acid and Formaline as a Fixitive for Animal Tis- 

 sues, by H. W. Norris 78 



Note on the Time of Sexual Maturity in Certain Unios, by H. M. Kelly 81 



The Influence of Chlorine as Chlorides in the Determination of Oxygen Consumed in the 



Analysis of Water, by J. B. Weems and J. C. Brown 85 



A Study of Some Cotton Seed Oils, by J. B. Weems and H.N. Grettenberg 89 



Diphenyl Ether Derivitives, by Alfred N. Cook 94 



Some Recent Analyses of Iowa Building Stones; also of Potable Waters, by Nicholas 



Knight 104 



Contribution to the Study of Reversible Reactions, by W. N. Stull no 



Depositional Equivalent of Hiatus at Base of our Coal Measures; and the Arkansan Series, 

 a New Terrane of the Carboniferous in the Western Interior Basin, by Charles R. 



Keyes ng 



Names of Coals West of the Mississippi River, by Charles R. Keyes 128 



Volcanic Necks of Piatigorsk, Southern Russia, by Charles R. Keyes 137 



A Comparison. of Media for the Quantitative Estimation of Bacteria in Milk, by C. H. 



Eckles. 



•■ 139 



A Method of Isolating and Counting Gas Producing Bacteria in Milk, by C. H. Eckles... 144 



The Total Solar Eclipse of May 28, 1900, by David E. Hadden 145 



Preliminary List of the Flowering Plants of Adair County, by James E. Graw 152 



The Juglandaceae of Iowa, by T. J. and M. F. L. Fitzpatrick ibo 



Betulaceae of Iowa, by T. J. and M. F. L. Fitzpatrick i6g 



The Fagacea of Iowa, by T. J. and M. F. L. Fitzpatrick 177 



Shrubs and Trees of Madison County, by H. A. Mueller 196 



A Terrace Formation in the Turkey River Valley in Fayette County, Iowa, by G E. Finch. 204 



Pure Food Laws, by C. O. Bates 206 



Notes on the Early Development of Astragalus Caryocarpus, by F. W. Faurot 210 



The Thistles of Iowa, with notes on a few other species, by L. H. Painmel 214 



Bacteriological Investigation of the Iowa State College Sewage, by L. R. Walker 240 



Notes on the Bacteriological .Analysis of Water, by L. H. Panimel 262 



Drift Exposure in Tama County, by T. E. Savage 27?. 



