512 



SCIENCE 



[N. S. Vol. XXXIV. No. 877 



College, and for the past year professor of 

 electrical engineering at the Clarkson School 

 of Technology, has been appointed assistant 

 professor of railway electrical engineering. 

 F. 0. Lincoln, S.B. (Mass. Inst. '00), E.M., 

 Ph.D. (Columbia '11), for three years pro- 

 fessor of geology and metallurgy at the New 

 Mexico School of Mines, for three years pro- 

 fessor of geology at the Montana State 

 School of Mines, and for the past year in 

 practise in New York City as consulting min- 

 ing engineer, has been appointed associate in 

 mining engineering. Paul Hanson, B.S. 

 (Mass. Inst. '03), for several years practising 

 sanitary engineer, has been appointed associ- 

 ate in sanitary engineering. G. A. Shook, 

 A.B. (Wisconsin '07), for the past four years 

 instructor in physics at Purdue University, 

 has been appointed instructor in physics. J. 

 W. Hornbeak, B.S. (111. Wesleyan '06), A.M. 

 (Illinois '09), assistant in physics at Cornell 

 University, has been appointed instructor in 

 physics. G. A. Goodenough has been pro- 

 moted from associate professor of mechanical 

 engineering to professor of thermodynamics, 

 and M. L. Enger from associate in theoretical 

 and applied mechanics to assistant professor 

 of theoretical and applied mechanics. 



New faculty appointments to the School of 

 Applied Science of the Carnegie Technical 

 Schools, Pittsburgh, for 1911-12, are : Charles 

 B. Stanton, assistant professor of railroad en- 

 gineering; Clyde T. Griswold, assistant pro- 

 fessor of mining engineering; Clinton J. 

 Davisson, instructor in physics; Arden B. 

 Holeomb, instructor in electrical engineering; 

 Joseph H. Cannon, instructor in electrical 

 engineering; H. J. Maclntire, instructor in 

 mechanical engineering; Edgar F. Leippe, 

 assistant instructor in machine design; 0. T. 

 Geckler, instructor in mathematics; J. A. 

 Fitzgerald, instructor in commercial practise 

 and statistics; Edwin C. Kemble, assistant 

 instructor in physics; Roy B. Ambrose, as- 

 sistant instructor in mechanical engineering 

 laboratory. 



Mr. G. E. Anderson has been promoted to 

 an associate professorship of physics, Mr. H. 

 W. Price to an associate professorship of elec- 



trical engineering and Mr. P. Gillespie to an 

 associate professorship of applied mechanics 

 at the University of Toronto. Mr. T. B. 

 Saunders has been appointed lecturer in verte- 

 brate embryology. 



DISCUSSION AND COBBESPONDENCE 



COUPLING VS. RANDOM SEGREGATION 



To THE Editor of Science: The suggestion 

 offered by Morgan, in Science of September 

 22, to account for the coupling and repulsion 

 of factors for various characters in inheritance 

 in such forms as Abraxas, Drosopliila, fowls, 

 sweet peas, etc., incites this note. 



Briefly Morgan's hypothesis is (1) that the 

 materials representing factors that couple are 

 " near together in a linear series " in the 

 chromosomes; (2) that, when pairs of pa- 

 rental chromosomes conjugate, " like regions 

 stand opposed"; (3) that "homologous 

 chromosomes twist around each other," but 

 that the separation of chromosomes is in a 

 single " plane " ; (4) that, thereby the " orig- 

 inal materials will, for short distances be more 

 likely to fall on the same side of the split," 

 while more remote regions will be as likely to 

 fall on one side as on the other; (5) that, in 

 consequence, whether characters are coupled 

 in inheritance or are independently inherited 

 depends upon the " linear distance apart of 

 the chromosomal materials that represent fac- 

 tors." 



Leaving for cytologists to determine what 

 has become of the " individuality " of the 

 chromosomes, we may well inquire whether 

 this hypothesis can account for the facts of 

 Mendelian inheritance as exhibited in coup- 

 ling, allelomorphism and independent segre- 

 gation of the factors that represent characters. 

 If parental chromosomes twist together and 

 then separate in a single plane so that mate- 

 rials near together in a linear series are 

 usually left together on one side of the split 

 while more remote materials fall by chance on 

 either side, it would seem that somewhere be- 

 tween these two regions the material repre- 

 senting some one character at least must -be 

 divided by the split so that part of it would 

 lie on one side and part on the other. That 



