In connection with the discussion of fertile eggs, I want to point out the fact that the whole subject of fertility as distinct from hatchability, is somewhat meaningless. The facts of the case are, that whatever factors in the care of the stock will get a large percentage fertile eggs, will also give hatchable eggs and vice versa. This is to be explained by the fact that most of the unfertile eggs tested out during incubation, are in reality dead germs in which death has occurred before the chick became visible to the naked eye. Such deaths should usually be ascribed to poor parentage, but may be caused by wrong storage or incubation. Likewise, it would not be just to credit all deaths after chicks became visible to wrong incubation, although the most of the blame probably belongs there. Likewise, with brooder chicks, we must divide the credit of their livability in an arbitrary fashion between parentage, incubation, and care after hatching. By the hatchability of eggs, we then mean the percentage of eggs set that hatch chicks able to walk and eat. By the livability of chicks, we mean the percentage of chicks hatched that live to the age of four weeks, after which they are subject to no greater death rate than adult chickens. By the livability of eggs, we mean the product of these two factors, i.e.: the percentage of chicks at four weeks of age based upon the total number of eggs set. As before mentioned, the fertility of eggs bears fairly definite relation to the hatchability, so likewise the hatchability bears a relation to the livability of chicks. When poor hatches occur because of weak germs, as because of faulty incubation, this same injury to the chick's organism is carried over and causes a larger death among the hatched chicks. Moreover, the relation between the two is not the same with all classes of hatches, but as hatches get poorer the mortality among the chicks increases at an accelerating rate. The following table gives a rough approximation of these ratios: Per cent. of Per cent. of chick Per cent. of egg Hatchability. Livability. Livability. 100 100 100 90 95 85 80 88 70 70 84 50 60 72 43 50 55 27 40 40 16 30 24 7 20 10 2 10 2 1