On Individual Differences in Chicken Blood

I. The existence of numerous individual serological differences in the blood of chickens has been established by several authors by-means of rabbit immune agglutinins, 1 immune isoantibodies, 2 and normal isoantibodies. 3 , 4 The most interesting and exhaustive studies were carried out by Todd, who demonstrated with the use of immune isoagglutinins an almost complete individual specificity —a result in harmony with his older experiments with White 5 on cattle blood. As is seen from the following tests, a differentiation of individual chicken blood can also be made without difficulty by using absorbed normal ox sera. The tests (Table I) show that the agglutinins present in normal serum permit of a differentiation of individual blood properties, since most of the 12 chicken bloods examined could be distinguished from each other. From some preliminary experiments it seems possible that the differentiation can be carried further by using various normal sera. As these findings suggested similar experiments with the blood of other species, tests were made with guinea-fowl and turkeys. Within these species as well, certain differences were noticed, but the variations were much less pronounced. If one would venture to offer an explanation for these facts, it might be suggested that possibly the greater diversity in the blood of chickens is correlated to the existence of a large number of somatic variations in this species, resuiting from extensive selective breeding and perhaps the derivation from several ancestral forms. II. A striking aspect of the experiments of Todd and White on cattle and of Todd on chicken blood is, as already mentioned, the large number of differences. This great diversity would seem less puzzling if it could be explained by the existence of more or less well defined serological factors, such as exist in human blood. 6 , 7