542 EVOLUTION, HEREDITY, EUGENICS 



fats of eggs and embryos approached that of black salamander; 3. 

 Color almost totally black. (These characters persisted.) 



Guyer and Smith injected pulped rabbit lenses into fowls, and 

 injected serum from those treated into pregnant rabbits, without 

 effect on the adult; the offspring showed nearly 15 per cent defective 

 eyes, suggesting antibodies. The defects were transmitted in 

 reciprocal in-'and-out crosses through nine generations. Szily, 

 J. Huxley, and other investigators have criticized the experiment 

 severely, and efforts at repetition on the part of several have failed 

 to procure similar results. 



Sumner used a cold room on mice to produce shorter tails and 

 feet. Offspring from gestation at ordinary temperature showed the 

 character in three cases, but in the fourth the appearance was 

 reversed. Pavlov trained mice to come for food at ringing of a bell; 

 the number of lessons was reduced from 300 in the first generation 

 to 100 in the second, 30 in the third, and 10 in the fourth. In later 

 generations as few as five lessons were required. Others have not 

 found training effects inherited. 



References 



Detlefsen, J. A. 1925. The Inheritance of acquired characters. 



Phys. Review, 5, pp. 244-278. 

 GoLDscHMiDT, R. 1929. Experimentelle Mutation und das Problem 



der sogenannten Parallel-induktion. Biol. Zbl., 49. 

 JoLLOs, V. 1930. Studien zum Evolutionsproblem. Biol. Zentr., Bd. 



50, H. 9, S. 541-554- 

 Mavor, J. W. 1921. On the elimination of the X-chromosome from the 



egg of Drosophila melanogaster by X-rays. Proc. Soc. Exp. Biol, and 



Med., vol. 18, pp. 301-304. 

 Muller, H. J. 1927. The Problem of Genie Modification. Z. indukt. 



Abstammungslehre, Supplbd. i. 

 Plough, H. 1917. The effect of temperature on crossing over in 



Drosophila. Jour. Exp. Zool., vol. 24, no. 2, pp. 147-209. 



Is There Such a Thing as Inheritance of Disease? — We must at 

 once distinguish between (i) prenatal infection; (2) prenatal injury 

 to the germ or the embryo; (3) the inheritance of weakness predis- 

 posing to disease; and, finally, (4) true inheritance due to germinal 

 transmission. 



1. Prenatal Infection. — This may occur through the mother in 

 utero or by the infection of either egg or sperm. In all probability, 



