Effect of Age, Sex and Individual Variability on Lymphoid Tissue of the Pancreas in White Leghorn Chickens ,

EVALUATION of the extravascular lymphoid areas which occur in avian tissues long has been an enigma to histologists, especially in relation to hemopoiesis and to avian lymphomatosis. Many investigators have considered these areas normal in that they were thought to perform the functions of mammalian lymph nodes (Danchakoff, 1916; Mjassojedoff, 1926; Jordan, 1935, 1936; Gibbs and Johnson, 1935). It also has been suggested that these “normal” lymphoid areas become hyperplastic and eventually form the lesions characteristic of lymphomatosis (Jordan, 1936; Johnson, 1934; Gibbs and Johnson, 1935). It is common knowledge that extravascular lymphoid foci appear in chickens with no pathology generally regarded indicative of lymphomatosis. Jungherr (1934, 1935) reported equal frequencies of lymphoid areas in the brain in control birds and in birds inoculated with cell suspensions from lymphoid tumors considered characteristic of lymphomatosis. Mjassojedoff (1926) noted that lymphoid areas in chickens differed from mammalian lymph nodes in that they . . .