lf,0 



THE AMEBIC AN NATURALIST 



[Vol. LIV 



heterozygous parents in the ratio of three normal to one 

 affected. 



4. It has been shown that heterozygous animals mated 

 to normals produce offspring of the same classes as them- 

 selves in equal numbers. Furthermore, it has been 

 proven that homozygous dominants can be extracted from 

 heterozygous parents and that they show no more tend- 

 ency to transmit the disease than individuals of normal 

 unrelated stock. 



5. Heterozygous animals are entirely normal in their 

 reaction and can be told from the homozygous only by 

 breeding tests. 



6. A survey of the literature relating to nervous de- 

 fects in man and other animals does not reveal any con- 

 dition corresponding exactly to congenital palsy. Some 

 of the conditions in pigeons, rodents and in man are sim- 

 ilar in that they are recessive in inheritance. 



REFERENCES 

 Batten, F. E., and D. Wilkinson. 



1914. Unusual Type of Hereditary Disease of the Nervous System 



genita. Brain, Vol. 36,' ppf 341-351. 

 Bonhote, J. L. 



1912. [On Waltzing Rats.] Proc. Zool. Soc. Lond., March, 1912, 

 pp. 6, 7. 

 Cursehmann, H. (Editor.) 



1915. Text-book on Nervous Diseases. English edition edited by 



Charles W. Burr. Philadelphia, 2 vols., xx + 1132 pp. 



Dana, C. L. 



1887. Hereditary Tremor, a Hitherto Undescribed Form of Motor 



1911. Heredity in Relation to Eugenics. New York, H< 



Company. Pp. xi + 298. 

 renport, C. B., and D. F. Weeks. 

 1911. A First Study of Inheritance in Epilepsy. Joi 



Mental Dis., Vol., 38, No. 11, pp. 641-670. 



Eugenics Record Office, pp. 1-30.) 



, Vol. 43, No. 1112, 



