214 



SCIENCE. 



[N. S. Vol. XXIV. No. 607. 



Treasurer — Professor H. E. Summers, of Iowa 

 State College, Ames. 



Secretary — Professor L. S. Ross, of Drake Uni- 

 versity, Des Moines. 



The meeting in 1907 will be held at Drake 

 University. 



The following program was presented: 



M. F. Arey: 'A Review of the Development of 

 Mineralogy.' 



H. VV. NoKBis : ' The Carotid Arteries and their 

 Relation to the Circle of Willis in the Cat.' 



N. Knight: 'A Study of Dolomite and Mag- 

 nesite with special reference to the Separation 

 of Calcium and Magnesium.' 



Bkuce Fink : ' Ecological Notes from an Illinois 

 Esker.' 



J. Fred Clark : ' The Disparity between Age 

 and Development in the Human Family.' ( Illus- 

 trated by pronounced cases due to thyroid mal- 

 formations. ) 



L. H. Pammel : ' Some Diseases of Rocky Moun- 

 tain Plants.' 



John L. Tilton: 'An Attempt to illustrate 

 Tides and Tidal Action.' 



J. E. ToDD: (a) 'More Light on the Origin of 

 the Missouri River Loess,' (b) 'Some Variant 

 Conclusions in Iowa Geology.' 



W. S. Hendeixson: {a) 'The Action of Bromic 

 Acid on Metals,' (6) 'Logarithmic Factors for 

 Use in Water Analysis,' (c) 'A List of Chemical 

 Periodicals in Iowa.' 



T. J. FiTZPATBiCK : ' The Liliacese of Iowa.' 



L. Begeman: 'Mutual Induction and Internal 

 Resistance of a Battery.' 



Bruce Fink: 'Lichens and Recent Conceptions 

 of Species.' 



T. E. Savage : ' Some Unusual Features of the 

 Maquoketa Shale in Jackson County, Iowa.' 



A. T. Erwin : ' Amelanchier almfoUa and its * 

 Cultivated Forms.' 



Paul Bartsch: 'The Iowa Ornithological 

 Literature of the Nineteenth Century.' 



Walter J. Meek: *A Study of the Choroid 

 Plexus.' 



Frank F. Almy: (a) 'The Effect of Pressure 

 on Lines in the Spectrum of Iron,' ( 6 ) 'A Simple 

 Demonstration of the Doppler Effect in Sound,' 

 (c) 'The Physical Laboratory of Iowa College.' 



G. E. Finch: 'A Portion of the lowan Drift 

 Border in Fayette County, Iowa.' 



B. A. Place : ' The Relation of the Motor Nerve 

 Endings to Voluntary Muscle in Amphibia.' 



Fred J. Seaver: 'Notes on the Discomycete 

 Flora of Iowa.' 



Charles R. Keyes: (a.)'Lime Creek Fauna of 

 Iowa in Southwestern United States and North- 

 ern Mexican Region.' ( 6 ) ' Geology of the 

 Corinth Canal Zone.' (c) 'Alternation of Fossil 

 Faunas.' 



J. E. Guthrie: 'The Collembolan Eye.' 



J. M. Lindly : ' Flowering Plants of Calcasieu 

 Parish, Louisiana.' 



F. A. Brown : ' Some Contributions to Madison 

 County Geology.' 



O. M. Oleson and M. P. Somes : ' Flora of 

 Webster County, Iowa.' 



K. E. Guthe: 'Electrical Units.' 



H. P. Baker : ' The Holding and Reclamation 

 of Sand Dunes by Tree Planting.' 



L. S. Ross: (a) 'The Food of Subterranean 

 Crustacea,' ( 6 ) ' Number of Bacteria in Des 

 Moines School Buildings.' 



B. 0. Gammon : ' Cladocera in the Vicinity of 

 Des Moines.' Presented by L. S. Ross. 



D. W. Morehouse : ' Photographic Accessories 

 of Drake University Equatorial.' Introduced by 

 L. S. Ross. 



C. 0. Bates : ' Municipal Hygiene — Part II., 

 Milk.' 



B. Shimek: (a) 'Notes on Certain Iowa Trees 

 and Shrubs,' ( & ) ' The Loess of the Missouri 

 Bluffs.' 



J. A. Udden : ' Cyclonic Distribution of Pre- 

 cipitation.' 



L. S. Eoss, 

 Secretary. 



DISCUSSION AND CORRESPONDENCE. 



THE mutation THEORY AGAIN. 



Certain objections to the mutation theory 

 of de Vries have called forth the wrath of 

 Professor C. S. Gager, and he emphatically 

 demands that this theory should be thoroughly 

 understood before we discuss it.^ With more 

 zeal than discretion he affirms that this lack 

 of understanding is shown in two recent ar- 

 ticles published in Science, one of which has 

 the present writer for its author;^ he calls 

 these articles a display of mental density, 

 claiming that the views of de Vries have been 

 misrepresented; but with reference to my own 

 paper he only succeeds in demonstrating that 

 he in turn has entirely failed to grasp the 



^ De Vries and his critics, in Science, July 20, 

 1906, p. 81 ff. 

 = Science, May 11, 1906, p. 746 ff. 



