R C. PUNNETT AND THE LATE MaJOR P. G. BAILEY 279 



Grade 5. R. de N. 2, Ch. t. 1. 



6. R. de N. 4, Cb. t. 2, Ch. r. 1, J. m. 1. 



7. Ch. t. 3, Ch. r. 2. 

 „ 8. Ch. t. 4, Ch. r. 3. 

 „ 9. Ch. r. 4, J. m. 2. 



„ 10. J. m. 2, S. roug. 1, S. jaun. 1. 

 „ 11. J. m. 4, S. roug. 2, S. jaun. 2. 

 „ 12. S. roug. 3, S. jaun. 3. 



These grades are of course arbitrary, and in passing from the lowest to the 

 highest there is no regular quantitative accession of colour. The difiFerence between 

 grades 2 and 3 for example is certainly much less than between grades 9 and 10. 

 Where the amount of colour is slight a difiFerence is more easily apprehended than 

 where the shade is deeper. 



In practice a difficulty arises from the fact that the tint of a given hen's eggs 

 often varies to some extent during her laying period. Our experience has been that 

 the eggs laid earlier in the series are generally rather darker than those laid later 

 on in the season, and in the case of the more deeply tinted eggs there may even be 

 a difference of several grades between those laid in March and those laid in July. 

 Sometimes also the first few eggs laid by a pullet are variable in tint. Our practice 

 therefore has been to neglect the first few eggs and to base our record on several 

 eggs laid in the earlier part of the season. Our experience has been that, in the 

 great majority of cases, such eggs show practically no variation in tint. 



In the case of a few birds a further difficulty has arisen in attempting to grade 

 the egg. In these cases a tinted egg is laid which has the appearance of being 

 covered with a delicate chalky film. That the texture of the shell plays a part in 

 the tint of the egg is obvious, but the extent to which the two are interdependent 

 would necessitate research directed upon this special point. In the case of these 

 "chalky" eggs we decided, after some hesitation, to record their grade as they 

 appeared when moistened and rubbed. After such treatment the egg appears several 

 grades darker than when fresh from the oviduct. 



We may now turn to the experimental results, taking first the 

 Leghorn-Langshan cross. Originally this was made between a Leghorn ? 

 and a Langshan j/*. The Leghorn belonged to the strain procured by 

 Mr Bateson from Mr Boys-Smith in 1900-01. Even at that time the 

 birds were closely inbred \ The strain was kept pure from admixture 

 with any other strain until it was used in 1910-11 for crossing with the 

 Langshan. By that time hens alone remained. Though large numbers 

 of chicks were hatched it was found impossible to raise a cockerel. The 

 healthiest survived until about one-third grown and then succumbed 

 to sudden and mysterious fits. The majority died soon after hatching. 

 Pullets were more easy to rear, though even here the mortality was 

 considerable. Those reared were slow growers, on the small side, and 



* Of. Bateson and Saunders, 1902, p. 92, where a pedigree is given. 



