Application of the quantum theory to 

 coupled electrons. — The success of the semi- 

 circular model of helium suggests that in the 

 case of coupled electrons the quantum theory- 

 should be applied not to the momentum of the 

 individual electrons according to the relation 

 fpdq = h/2Tr, but rather to the momentum 

 which by being relayed from one electron to 

 another, passes in each direction around the 

 nucleus. 



4. Studies on inbreeding. IV. Effects of in- 

 breeding on the growth and variability in 

 body weight of the albino rat. .Helen D. 

 King; Jour. Exp. Zool., 29, No. 1 (1919). 



ABSTRACT 



Effects of inbreeding on the growth and 

 variability in body weight of the albino rat. — 

 In continuation of previous work, data are 

 given concerning over 600 rats belonging to 

 the sixteenth to twenty-fifth generations of a 

 strain bred brother to sister from the same 

 litter only. Allowing for the effect of certain 

 unfavorable conditions, determined by control 

 rats, the results confirm previous conclusions 

 and show that close inbreeding continued for 

 25 generations has not produced any deteriora- 

 tion in the stock as regards the growth curve, 

 the body weight, the variability of body weight 

 for various ages, and the relative behavior of 

 the sexes in these respects. Selected rats were 

 used as the parents of each generation. If 

 there is any tendency to deterioration it was 

 counteracted in these experiments by the se- 

 lection employed. 



Effect of nutrition on the growth and varia- 

 bility in body weight of the albino rat. — Rats 

 are particularly sensitive to food conditions. 

 Alfalfa, cottonseed and linseed meal were 

 found to be injurious. A change from a satis- 

 factory diet to one less suitable resulted in a 



