TABLE OF CONTENTS 
Page 
Letter of Transmittal . iii 
Table of Contents v 
Officers of the Academy ...... vi 
Membership of the Academy vii 
N ecrology — Ferdinand Reppert xi 
Proceedin gs of the Eighteenth Annual Session 1 
Presidential Address, by B . Fink. 11 
The Animal Cell in the Light of Recent Work, by Gilbert L. Houser. 39 
The Importance of Vital Statistics in the Study of Social Science, by Gershom H. Hill. 55 
A Geological Situation in the Lava Flow, with reference to the Vegetation, by Harriet 
M. Clearman. 66 
The Furcula in the Collembola, by J. E. Guthrie 69 
Stereoscopic Projection in Natural Colors, by C. F. Lorenz.... 75 
A Contribution to our Knowledge of the Development of Prunus Americana, by R. E. 
Buchanan 77 
The So-called Dorsotrachealis Branch of the Seventh Cranial Nerve in Amphiuma, by 
H. W. N orris 95 
The Vagus and Anterior Spinal Nerves in Amphiuma, by H. W. Norris 98 
A Buried Peat Bed and Associated Deposits in Dodge Township, Union County, by 
T. E. Savage 103 
Some Bacteriological Examinations of Iowa Waters, byL. H. Pammel, Edna King 
and R. E. Buchanan Ill 
Some Features in the Analysis of Dolomite Rocks, by Nicholas Knight 127 
The Sioux City Water Supply, by Alfred N. Cook 133 
A New Deposit of Fuller’s Earth, by Alfred N. Cook 135 
The Lichen Flora of the “Ledges”, Boone county, Iowa, by Katy A. Miller 139 
A Method of Determining Chloric Acid, by W. S. Hendrixson 147 
The Action of Chloric Acid on Metals, by W. S. Hendrixson 150 
Periodical Literature in Iowa on the Subject of Chemistry, by W. S. Hendrixson 162 
Regeneration in the Crayfish, by John J. Lambert 165 
A Chemical Study of Rhus glabra, by Arthur W. Martin 171 
Notes on the Position of Nileus vigilans in Strata at Elgin, Iowa, by G. E. Finch 179 
Action of Sodium Thiosulphate on Silver Salts, by W. M. Barr 183 
New Method of Cohesion of Water and Adhesion of Mercury Apparatus, by Edwin 
Morrison..... 191 
A Convenient Voltaic Cell, byL. Begeman 195 
The Flora of Emmet County, by R. I. Cratty • 201 
Remarkable Occurrence of Aurichalcite, by Charles R. Keyes 252 
Certain Ba in Features of the High Plateau Region of Southwestern United States, by 
Charles R. Keyes ....... ..... 254 
Note on the Carboniferous Faunas of the Mississippi Valley in the Rocky Mountain 
Region, by Charles R. Keyes .......... — 258 
A Preliminary List of the Flowering Plants of Madison county, by H. A. Mueller 261 
*A Synthesis of Ethyl Alcohol from Acetylene, by John S. Frazee 
Index 281 
* Paper omitted from this volume on account of lack of space. 
