788 



SCIENCE 



[N. S. Vol. XXXVlIi. No. 987 



tina^ that it is irrevocably decided during the 

 growth period of an egg whether the female 

 that hatches from that egg will be a male- 

 producer or a female-producer. This is actu- 

 ally proved, it is true, only so far as the effect 

 of chemical substances is concerned. But I 

 am unable to take comfort in the view that sex 

 is determined at a given moment beyond the 

 possibility of reversal by chemical substances, 

 while it is still open to alteration by other 

 external agents. If sex is determined thus a 

 generation in advance in Asplanchna, as in 

 Hydatina, the starvation experiments referred 

 to above could not have produced positive 

 results; the starvation should have been prac- 

 tised on the mother of the desired male- 

 producer. 



In another experiment Mitchell starves a 

 number of young females for a few hours 

 after birth. The first few daughters in each 

 of nine families are used as controls (well fed) ; 

 they include six male-producers out of a total 

 of 39. The later daughters of the same 

 families are starved; 51 out of 68 prove to be 

 male-producers. The author attributes the 

 higher proportion of male-producers in the 

 latter lot to the check upon nutrition. But, 

 waiving the objection of a rather small number 

 of individuals, another explanation is at hand. 

 It has been shown' from 349 families of 

 Hydatina, comprising about twelve thousand 

 individuals, that the first few daughters of a 

 family are much less likely to be male-pro- 

 ducers than are the later members. If the 

 same relation holds in Asplanchna, the num- 

 bers of male-producers obtained in the experi- 

 ment described are about what would have 

 been expected if starvation had not been prac- 

 tised. 



In offering this criticism of Mitchell's work 

 I do so' in no carping spirit. It is gratifying 

 to find some one using the excellent material 

 which Asplanchna affords in an attempt to 

 solve fundamental problems. I have sought 



sShuU, A. F., "Studies, etc., III. Internal 

 Factors Affecting the Proportion of Male-pro- 

 ducers," Jour. Exp. Zool., Vol. 12, No. 2, Feb- 

 ruary, 1912. 



3 Shull, A. F., ' ' Studies, etc. ' ' I., Jour. Exp. 

 Zool., Vol. 8, No. 3, May, 1910. 



only to show wherein lie the weaknesses of the 

 evidence. A. Franklin Shull 



tjNIVEESITT OF MICHIGAN 



THE AMESICAN PHYSICAL SOCIETY 



A REGULAR meeting of the Physical Society was 

 held in Fayerweather Hall, Columbia University, 

 New York City, on Saturday, October 18, 1913. 

 The following papers were presented: 



"The Vapor Pressure of Metallic Tungsten," 

 by Irving Langmuir. 



"The Form of the Ionization by Impact Func- 

 tion, a/p=/ {x/p)," by Bergen Davis. 



"Change of State Solid-liquid at High Pres- 

 sure," by P. W. Bridgman. 



"Notes on Some Integrating Methods in Alter- 

 nating Current Testing," by Frederick Bedell. 



"Silvered Quartz Fibers of Low Eesistance 

 Obtained by Cathode Spray," by Horatio B. Wil- 

 liams. 



"The Critical Ranges Aj and A3 of Pure 

 Iron," by Gr. K. Burgess and J. J. Crowe. 



"A Spectrophotometrie Study of the Absorp- 

 tion, Fluorescence and Surface Color of Mag- 

 nesium Platinum Cyanide," by Frances G. Wick. 



"Examination of the Omnicolored Screen Plate 

 by Means of Microscope and Spectroscope," by 

 John B. Taylor. 



"Eelativity Theory — General Dynamical Prin- 

 ciples," by Richard C. Tolman. (By title.) 



"The Hall Effect in Liquid and Solid Mer- 

 cury, ' ' by W. N. Fenninger. 



"An Electrolytic Determination of the Ratio of 

 Silver to Iodine and the Value of the Faraday," 

 by G. W. Vinal and S. J. Bates. 



"Effect of Amalgamation on the Contact 

 E.M.F. of Metals," by F. J. Rogers. 



"Eelativity Theory; The Equipartition Law in 

 a System of Particles," by Richard C. Tolman. 

 (By title.) 



"Failure of Color Photography by Commercial 

 Screen-plate Methods for Spectroscopic Records," 

 by John B. Taylor. 



"Condition Involving a Decrease of Primary 

 Current with Increasing Secondary Current," by 

 F. J. Rogers. 



"Experiments on the Magnetic Field of Two 

 Electromagnets in Rotation, " by S. J. Barnett. 



"The Effect of Spae« Charge and Residual 

 Gases on the Thermionic Current in a High 

 Vacuum," by Irving Langmuir. 



Alfred D. Cole, 



Secretary 



