November 15, 1912] 



SCIENCE 



683 



evening sixteen members gathered at the usual 

 dinner. 



The following papers were read at this meeting : 



H. W. Eeddiek : ' ' Systems of plane curves 

 whose intrinsic equations are analogous to the 

 intrinsic equation of an isothermal system. ' ' 



L. L. Dines: "Note concerning a theorem on 

 implicit functions. ' ' 



Ij. L. Dines : ' ' Singular points of space curves 

 defined as the intersections of surfaces. ' ' 



E. T. Bell: "On Liouville's theorems concern- 

 ing certain numerical functions. ' ' 



E. T. Bell : ' ' The representation of a number 

 as a sum of squares. ' ' 



G. E. Clements : ' ' Implicit functions defined by 

 equations with vanishing Jacobian. Supplemen- 

 tary note. ' ' 



Edward Kasner: "Note on contact transforma- 

 tions of space." 



E. H. Taylor: "An extension of a theorem of 

 PainlevS. ' ' 



L. S. Dederick : "On the character of a trans- 

 formation in the neighborhood of a point where 

 its Jacobian vanishes." 



Vito Volterra : ' ' Some integral equations. ' ' 



W. F. Osgood: "Proof of the existence of func- 

 tions belonging to a given automorphie group." 



G. D. Birkhoff : ' ' Proof of Poincar6 's geometric 

 theorem. ' ' 



E. V. Huntington: "A set of postulates for 

 abstract geometry in terms of the simple relation 

 of inclusion." 



Dunham Jackson: "On the degree of con- 

 vergence of related Fourier series." 



A. A. Bennett: "Note on the solution of linear 

 algebraic equations in positive numbers." 



The San Francisco Section of the society held 

 its regular fall meeting also on October 26 at the 

 University of California. The regular meeting of 

 the Southwestern Section will be held at the Uni- 

 versity of Kansas on November 30. The annual 

 meeting of the society, including that of the 

 Chicago Section, will be held at Cleveland, Ohio, 

 December 31 to January 2. y. N. Cole 



Secretary 



THE BOTANICAL SOCIETY OF VFASHINGTON 



A SPECIAL meeting of the society was held Sep- 

 tember 18, 1912, in honor of Professor Hugo de 

 Vries, of the Hortus Botanicus, Amsterdam, who 

 addressed the Society on "The Future of Plant 

 Breeding as related to Agricultural Production. ' ' 

 At the close of the address brief appreciative re- 



marks were made by Professor W. M. Hays, Dr. 

 E. F. Smith, Professor W. J. Spillman and Mr. F. 

 V. CoviUe. 



The S2d regular meeting was held at the Cosmos 

 Club, Thursday, October 17, 1912, at 8:00 P.M., 

 Mr. C. S. Scofield, president pro tern., presiding. 

 Nineteen members were present. Mr. W. H. 

 Lamb, of the Forest Service, was elected to mem- 

 bership. The following papers were read: 



The Cotton of the Hopi Indians: F. L. Lewton. 



This paper will be published in full in Smith- 

 sonian Miscellaneous Collections, Vol. 60, No. 6. 

 A Botanical Trip to the Sevier Forest, Southern 



Utah: W. W. Eggleston. 

 Vamping-off of Coniferous Seedlings: C. P. 



Hartley. 



With the exception of the cedars, damping-off 

 of seedlings is a serious hindrance to the raising 

 of conifer seedlings. Surfacing beds with gravel 

 tends to decrease the trouble. The disease is gen- 

 erally worst under moist conditions, but a well- 

 drained nursery in dry climate in southwestern 

 Kansas has suffered especially heavy loss from 

 damping-off parasites. No positive control method 

 has ever been developed for general use. 



In western porous soils damping-off is simply a 

 root-rot of very young seedlings, which may attack 

 at any point from the ground surface to several 

 inches below. Seedlings several weeks old may 

 have the younger parts of their roots rotted and 

 yet survive. 



Fythium deiaryanum appears to be the most 

 dangerous parasite in western nurseries. BMsoc- 

 tonia sp., Fusarimm sp., and probably Tricho- 

 derma Ugnorum, also cause damping-off. Pythium 

 and Ehizoctonia have been successfully inocu- 

 lated on autoclaved soil; but inoculations do not 

 succeed uniformly on unsterilized soil, due prob- 

 ably to competition of bacteria and other fungi. 

 Bhizoctonia loses parasitism in culture and differ- 

 ent strains vary greatly in virulence. 



All active Fythium in nursery soil can be killed 

 very cheaply by means of fungicides. Heat, and 

 fungicides which break down soon after applica- 

 tion, such as mercuric chloride, or acids and cop- 

 per salts followed by lime, are not effective in the 

 west, because Fythium often reinfects such dis- 

 infected soil, running through it rapidly before 

 seedlings raised on it develop resistance. This 

 reinfection at least sometimes takes place through 

 the air, and is difficult to prevent under nursery 

 conditions. Excellent results have been obtained 

 by treating teds before seeding with sulfuric acid 



