Sept. iS, 1916 



Dwarf Eggs 



983 



membrane. The method employed was the one in routine use at this 

 laboratory (3) . The egg was first weighed; then the egg was broken and 

 the parts separated. The yolk and shell were wiped as dry as possible 

 with filter paper and weighed. The weight of albumen was determined 

 by difference. The weights of the parts were determined for 16 of the 

 small-yolked dwarf eggs. This number is so small that the variation 

 and correlation were studied directly from the ungrouped data. These 

 data are given in Table III. 



The frequency constants calculated from the distributions in Table II 

 and from the data in Table III are given in Table IV. 



Table III.- 



-Weight of egg and of each of the egg parts for the 16 dwarf eggs on which 

 these data were taken 



Egg No. 



Weight of 



Weight of 

 yolk. 



Weight of 

 albumen. 



Weight of 

 shell. 



I 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



x 3 



14 



15 



16 



Mean 



Gm. 

 20. OO 



17. 00 



18. 40 

 24. 50 

 20. 00 

 22. 50 

 24.85 

 29. 00 



24- 75 

 30.00 

 29. 00 



31. 00 



32- 5° 



3°-33 



32. 00 

 34. 00 



26. 24 ±0. 82 



Gm. 



O.85 



1. OO 



1.85 



2. 19 



2. 50 



3-55 



4-37 



5° 



53 



00 



5° 

 5° 

 5° 

 -:° 



OO 

 OO 



4. 27 ±0.34 



65 



OO 



So 

 22 



OO 



25 



38 



05 



75 

 5° 

 5° 



The variation constants were not calculated for cylindrical eggs 

 either with or without yolk, since the number is so small that these 

 constants would be meaningless. The arithmetical mean in these cases 

 was calculated directly from the data. For the sake of comparison the 

 Table IV also gives the constants determined by Curtis (4) from the 3,180 

 normal eggs laid by a flock of 22 Barred Plymouth Rock birds during 

 their pullet year, and the constants determined by Pearl and Surface (20) 

 for the 450 eggs laid by an 850-bird flock of Barred Plymouth Rock 

 pullets on February 12, 1908. The constants from the two series agree 

 closely and may be considered a fair measure of the variation in the 

 physical characters of the normal Barred Plymouth Rock egg. Since 

 the second set of constants is based on a group of eggs, no two of which 

 were laid by the same bird, they are theoretically the better measure of 

 a random sample of Barred Plymouth Rock eggs. 



