64 



The Journal of Heredity 



father grew slowly, although they ate 

 freely and appeared to be well. They 

 remained small and below the average 

 in weight. Three were males and one 

 was a female. 



One of the males was mated with a 

 normal female and two normal young 

 resulted. He was then mated with a 

 female from an alcoholic father and she 

 gave birth to two small young; one of 

 these offspring was onh' half size and 

 very excitable. He was then mated 

 with a female from an alcoholic mother 

 and one small young was produced. 



A second one of the three males was 

 mated with a normal female which pro- 

 duced one large apparently normal 

 offspring. He was then mated with a 

 female from an alcoholic father and two 

 small young resulted, one of which 

 died within five days and the other is 

 weak and nervous. He was again 

 mated with a normal female and one 

 normal young was produced. 



The third male was mated with his 

 sister and she gave birth to three young. 

 One of the young died when one day 

 old, having been in a constant tremor 

 since its birth; another lived for nine 

 days but whenever it attempted to 

 walk it was seized with spasmodic con- 

 tractions; the third sjjecimen exhibited 

 the same nervous manifestations and 

 was completely eyeless. This animal 

 died eight days after birth and an 

 examination of the brain showed an 

 entire absence of optic tracts. 



In the development of this animal it 

 is proVjable that the optic vesicles were 

 suppressed and never arose from the 

 brain. Thus, no eyes, optic ncrv^es, or 

 optic tracts could have formed. This 

 particular eyeless condition in these 



experiments is of interest since one is 

 readily able to suppress the origin of 

 the optic vesicles in fish and chicken 

 embryos by similarly weakening the 

 embryo with treatments of alcohol, 

 ether, etc. 



The mother of these offspring was 

 remated with her brother, but she died 

 six weeks later, not becoming pregnant. 

 She was in an emaciated condition but had 

 always been less than half normal 

 weight. 



The three extremely weak and de- 

 fective offspring were doubtless due to 

 the fact that both of their parents had 

 similarly weakened or injured con- 

 stitutions, having resulted from a single 

 mating of a normal female with an 

 alcoholized male. The eyeless offspring 

 and the other two nervous non-viable 

 individuals should not be interpreted as 

 due merely to the fact that their parents 

 were brother and sister. Several normal 

 matings of brother and sister have been 

 made during the experiment and per- 

 fectly healthy offspring have been pro- 

 duced. In the studies of heredity con- 

 ducted on guinea-pigs brother and sister 

 are crossed with impunity, in no way 

 weakening their offspring. The sig- 

 nificant i)oint in the ])rcscnt considera- 

 tion is that the two animals coming from 

 the same mother and treated father 

 may have had similar weaknesses or 

 defects and the combination of two 

 such indi\'iduals resulted in offspring 

 which exhibited these defects to a more 

 decided extent. The three animals 

 were far more defective than their 

 parents and owed their defects to the 

 modified condition of the genn cells of 

 the grandfather from, which they de- 

 scended. 



PLANT BREEDING SECTION TO MEET 



A meeting of the Plant Breeding Section of the American Genetic ^Association 

 will be held on February 20 and 21, in connection with the National Corn Expo- 

 sition at Dallas, Texas. It is open to all members of the association, and contri- 

 butions will be welcomed. Those who wish to send or read papers should communi- 

 cate the titles at once to C. P. Bull, secretary of the exposition, at Dallas, together 

 with an estimate of the length. Other infomiation can be secured from A. W. 

 Gilbert of Cornell University, chairman of the research committee on ])lant l)reed- 

 ing. 



