58 MAYNIE R. CURTIS. 



during October when the pullets which are coming on to lay are 

 immature. This observation does not agree with the statements 

 of Immerman, 1 Panum 2 and Parker 3 that the greatest number 

 of double-yolked eggs occur in the warmer part of the year. 

 Immerman, however, recognized the fact that the seasons when 

 he obtained the largest number of double-yolked eggs coincided 

 with the periods of highest egg production. He believed that 

 the laying of double-yolked eggs occurred during the entire 

 laying period and that no season had an especial influence on 

 their production. Since the eggs on which these workers base 

 their statements were collected from the market, or brought 

 to them by their friends, it is likely that they did not receive 

 the double-yolked pullet eggs, which are often not distinguishable 

 externally from the single-yolked eggs of the year-old and 

 two-year-old hens. 



It is also possible that the birds in the part of the country 

 where these people worked were so bred and handled that they 

 did not begin to lay until much later than birds specially bred 

 for winter production. 



The second observation which suggests that an immature 

 bird is more likely to produce double-yolked eggs than one which 

 is mature was made upon the eggs of a single pullet which began 

 to lay when she was exactly three months old and before she 

 had assumed her adult plumage. The first ten eggs of this 

 pullet were kindly presented to this station by the owner of 

 the bird, Mr. Walter Gerald, of Unity, Maine. All of these ten 

 eggs were smaller than a normal pullet's egg but the four largest 

 of them contained two yolks. This pullet, which began to lay 

 when much less mature than any of the pullets which have been 

 raised on the station plant, produced more double-yolked eggs 

 than have been laid by any of these birds. This bird may, of 

 course, be absolutely abnormal in respect to the production of 

 double-yolked eggs. 



1 Immerman, F., " Uber Doppeleier beim Huhn," Inaugural-Dissertation, Basel, 

 43 pp., 1899. 



2 Panum, P. L., " Untersuchungen iiber die Entstehung der Missbildungen 

 zuniichst in den Eiern der Vogel," Berlin, 260 pp., 1860. 



3 Parker, G. H., " Double Hen's Eggs," American Naturalist, Vol. XL., pp. 13-25, 

 1906. 



