266 MAINE AGRICULTURAL EXPERIMENT STATION. I912. 



number of young per birth in the breeding history of the sam(? 

 individual female, unless one is prepared to assume a very com- 

 plicated mechanism of heredity for this character. 



The relation of heredity to multiple gestation in man has also 

 been discussed by Wakley," Lop/* Naegeli-Akerblom/" and 

 Rosenfeld'^ particularly, and 'by a number of other medical and 

 and anthropological writers incidentally. 



An interesting case of apparent inheritance of a tendency to 

 twin bearing in cattle has recently been reported by Went- 

 worth." The family of cattle concerned has been bred on an 

 old fann near Cocheco, New Hampshire. "The foundress of 

 the family was a grade Holstein cow, herself a twin about seven 

 years old. She has been on the farm ever since she was dropped 

 and has given birth to seven calves. Her first service was to a 

 Guernsey bull and resulted in a pair of yellow and white 

 heifers one of which is now in the herd. Her second mating 

 to a red Shorthorn bull resulted in a single black and white bull 

 calf that was vealed. An Ayrshire bull sired her third calves, 

 twin black and white bulls, but neither of these were good 

 enough to raise. Her fourth service was to a Holstein bull and 

 from it she produced twin black and white heifers that promise 

 well as milkers." 



"The yellow and white twin first produced by the old cow is 

 now four years old and has twice borne twins. To an Ayrshire 

 bull she produced a pair of yellow and white bull calves that 

 early went to the butcher, and to a Holstein bull she gave 

 birth to twin black and white heifers last December." 



The .further collection of accurate data bearing upon this 

 question of the inheritance of a tendency to multiple gestation 

 is greatly to be desired. 



Data on a second problem in inheritance are presented by 

 cases of multiple gestation, namely that of the limits of heredi- 



"Wakley, Thomas. The Influence of Inheritance on the Tendency 

 to have Twins. Lancet, 1895, Vol. II, pp. 1289-1290. 



"Lop. Quelques chiffres sur I'heredite de la grossesse jumellaire, 

 Congres periodique de gyn. obstetr. et de pediatric. Marseille, 1899. 



"Naegeli-Akerblom. Die Geminitat in ihren erblichen Beziehungen, 

 Virchow's Arch. Bd. 170, 1902. 



^"Rosenfeld. Zur Frage der vererblichen Aniage zur Mehrlingsge- 

 burten. Zeitschr. f. Geburtsh. u. Gynak. Bd. 50, 1903. 



"Wentworth, E. N. Twins in Three Generations. Breeder's Gazette, 

 Vol. Ixii, p. 133, July 24, 1912. 



