30 



The Journal of Heredity 



grasshoppers, and the chromosome com- 

 plex of their germ-cells. 



The crosses of Zebu with native cattle 

 have been studied from a genetic point 

 of view by this department, and a coop- 

 erative experiment in the inheritance 

 behavior of crosses of Karakul and 

 Lincoln sheep has been started. 



From the Utah station. Director E. D. 

 Ball writes: 



"By breeding fowls, we are attempt- 

 ing to determine the possibility of 

 improvement of the laying qualities of 

 hens by continuous selection. In order 

 to accom])lish this it was considered 

 necessary first to establish what the 

 original laying capacity of an unsclccted 

 flock of hens really was, as study of all 

 of the records available did not seem to 

 throw very much light on this question. 

 Most of the records have been based 

 entirely on the first year production, 

 and the first year production as is shown 

 in ovir Bulletin 135, apjjears to be a very 

 poor indication of the laying capacity of 

 a given individual or of a given strain of 

 fowls. Therefore, the first object sought 

 was to keep a sufficient number of 

 flocks of unselected fowls under as near 

 as possible normal conditions, to deter- 

 mine through a series of years what 

 production could be normally expected 

 from a flock and what the range of 

 variation due to seasonal influences, 

 individual differences, etc., really was. 

 Bulletin 135 contains a svimmary of this 

 work to date. It will be continued for 

 some time in order to get still more 

 accurate data and especially to deter- 

 mine the actual longevity and laying 

 period of the White T>cghorn hen. 



PKRIODICAL KGC; RECORDS. 



"This year's records, which are not 

 included in this bulletin, arc strikingly 

 confirmatory of the general results. 

 The records this year under identical 

 care and attention of last year have 

 fallen almost to the poor record of 1911, 

 while every indication ujj to date is that 

 next year's rec(jrd will again be a good 

 one, more forcibly illustrating the 

 periodicity in production. We have in 

 manuscrijjt at the present time a 

 detailed study of the winter egg pro- 

 duction of these same flocks of hens in 



an attem])t to determine whether there 

 is an\' possibility of disco\-ering a 

 Mendelian factor, as is claimed by the 

 Maine Station. We have been unable 

 to find any Mendelism in the inheritance 

 of this characteristic. Taking the 

 records of hens from three to seven 

 years and com]jaring them, we find that 

 the individual fluctuates up and down 

 in the same way that the flocks do, and 

 that our winter egg production is even 

 more variable than our total, that entire 

 flocks have produced as low as 15 to 17 

 eggs in the first winter and from 35 to 40 

 the second year. According to Dr. 

 Pearl's conclusion, it would seem that 

 they must have acquired the high la>-ing 

 unit the second year. A third portion 

 of this bulletin will take up the possi- 

 bilities of improvement by selection, — 

 it is, of course, only a preliminary study 

 as it will be necessary to carry on the 

 work many years to obviate seasonal 

 variations and to select strains. We 

 have, however, been able materially to 

 modify productions by strain selection 

 based on three years or more of produc- 

 tion, and tested by an equal amount of 

 production in the offspring. " 



A series of experiments of far-reaching 

 importance, which should attract the 

 attention of eugenists as well as live- 

 stock breeders, is under way at Missouri. 

 "The influence of the age of the parents 

 upon the oft'spring is at the present time 

 largely a matter of o])inion. A careful 

 study is being made of the ultimate 

 effect of mating young animals con- 

 tinviously. It is proposed to determine 

 first the effect upon the immediate 

 offsjjring; second the effect u])on the 

 mother; third the effect, if any, upon 

 the race. Some interesting results have 

 already been secured, ])articularl\' ujion 

 the effect of early mating ui)on the 

 mother and immediate offsi)ring." "The 

 most imi)ortant ])ositive result is ap- 

 parently the stunting effect on the young 

 mother. Careful measurements indi- 

 cate that early jjrcgnancy interferes 

 with the rate of growth and the ultimate 

 development of the maternal i)arent." 

 Several hundred animals are included in 

 this exi)eriment tt) date. 



Sex-linked characters are being traced 

 in poullrx', wliere llu\\- have been found 



