May 2, 1919] 



SCIENCE 



429 



From the data presented in the table it ap- 

 pears that hig-her production is correlated very 

 definitely ^vith higher percentages of increase 

 in egg-weight. The maximum group-produc- 

 tion (147) occurred in those hens whose mean 

 increase in egg- weight was above 13 per cent, 

 in the '" 10-egg test." Selecting above 10 per 

 cent, gave seven birds whose mean production 

 was 143 eggs. Selecting above 6 per cent, 

 gave 12 hens whose mean production was 139 

 eggs. On the other hand selecting the hens 

 which gave a decrease in egg-weight (" < 

 per cent.," in the table), gave five hens with a 

 mean production of only 108. 



The superiority of the " 10-^g test " in es- 

 tablishing the correlation with numerical pro- 

 duction in this instance clearly brings the 

 testing of egg-production of hens into the 

 same class with testing milk-production of 

 dairy cows, in which case Gavin and also 

 Wilson have pointed out that under suitable 

 conditions the one day test may be of greater 

 value than the seven-day, the 30-day or the 

 year test. 



With these points openly in mind, and only 

 with the purpose of stimulating further in- 

 vestigation and discussion, the author presents 

 the following brief summary of his results 

 with a single flock as expressing a biological 

 fact which, if later proved to be of general 

 application, may take its place as a funda- 

 mental law of production in the domestic 

 fowl: 



The innate egg-producing ability of a hen is 

 manifested, not only by the number of eggs 

 laid within a year, or within some longer or 

 shorter period of time, but also by the degree 

 of increase or of decrease in the mean weight 

 of her eggs, when this increase or decrease 

 (calculated as a percentage-increase or per- 

 centage-decrease) is measured at those periods 

 of laying (the vernal and autumnal maxima) 

 .characterized by the markedly increased lay- 

 ing of the flock; and on this basis, groups 

 of hens characterized by higher producing 

 ability can be differentiated as accurately as, 

 and more easily than by other known means. 



The validity of this proposed law of pro- 



duction is supported by detailed evidence in an 

 article to appear in The American Naturalist. 

 Philip Hadley 

 r. i. aoricultubal experiment station 



SOCIETIES AND ACADEMIES 



THE NATIONAL ACADEMY OF SCIENCES 



The program of scientific sessions of the 

 meeting held in Washington on April 28, 29 

 and 30, was as follows: 



MONDAY, APRIL 28 



Morning Session 



Alfred G. Mayor: The age of the fringing reef of 

 Tutuila, American Samoa. 



Charles D. Walcott: Seaweeds and sponges of 

 the Middle Cambrian. 



Robert G. Aitken: The speetra of the visual bi- 

 nary stars. 



George E. Hale, P. Ellerman, S. B. Nicholson 

 and A. H. Joy: The magnetic polarity of sun 

 spots. 



Walter S. Adams and A. H. Joy : The motions in 

 space of some stars of high radial velocity. 



Walter S. Adams and G. Stromberg: The use of 

 spectroscopic method for determining the paral- 

 laxes of the brighter stars. 



ADRLiAN VAN Maanen (introduced by George E. 

 Hale) : Evidence of stream-motion afforded bv 

 the faint stars in the Orion nebula. 



Graham Lusk and H. V. Atkinson: The produc- 

 tion of fat from protein after giving meat in 

 large quantity to a dog. 



William S. H.\lsted: End-to-end anastomosis of 

 the intestine — experimental study. 



Robert M. Yerkes (introduced by George E. 

 Hale) : Psychological examining in the United 

 States Army. 



Afternoon Session 



Frederick H. Seares (introduced by George E. 

 Hale) : Relation between color and luminosity 

 for stars of the same spectral type. 



Frederick H. Seares, A. van Maanen and F. 

 Ellerman (introduced by George E. Hale) : 

 Deviations of the sun 's general magnetic field 

 from that of a uniformly magnetized sphere. 



W. W. Campbell: The solar corona. 



Herbert E. Gregory (introduced by W. M. Davis) : 

 Plans for exploration of the Pacific. 



Francis G. Benedict, W. R. Miles and Alice 

 Johnson: The temperature of the human skin. 



