Discussion on the Pathology and Treatment of Hæmopathies, Including Leukæmias, of Man and Animals

Abstract

The difference between hæmopathies (which originate in the blood-forming tissues) and blood-diseases (which develop in the blood-stream) is explained and illustrated by examples and specimens. Primary anæmia caused by the hyperplasia of the erythroblastic tissues in the marrow occurs in fowls as erythromyelosis. This condition can be experimentally transmitted, though inoculation in fowls may reproduce the anæmic disease, or give rise to a persistent polyerythrocythæmia. On farms erythromyelosis is often, but not always, associated with the cestode, Davainea proglottina. Secondary anæmia develops in splenectomized rats following the invasion of the erythrocytes by Bartonella muris. The subsequent erythrocytolysis may induce hæmoglobinuria, similar to that occurring in man and cattle as the result of certain hæmic infections. Oligoerythrocythæmia is frequently seen in fowls associated with leucocythæmia; the deficiency of the red blood-corpuscles is due to the pressure on the erythroblastic sinusoids, by the proliferation of the myeloblastic or lymphoblastic tissues in the marrow. Lymphocythæmia (and lymphomatosis) have been observed in canaries, fowls, mice and guinea-pigs. The conditions can be experimentally transmitted within the species; inoculation with lymphocythæmic blood may reproduce the hæmic type or induce the development of scattered tumour-like deposits (lymphomatosis). Whichever type of lesion results, the pathological cell unit is one of the lymphoblast-lymphocyte series. Fowl leucocythæmia originates through the morbid proliferation and premature entry into the circulation of cells of the myeloblast-granulocyte series. On inoculation in fowls the original leucocythæmia may be reproduced; rarely there follows the development of localized deposits of myeloblastic cells in the skin. As these diseases of the blood-forming system, and those occurring in man and cattle offer many striking resemblances, it may be suggested that the determination of the origin of the particular type of cell encountered should serve as guide to diagnosis and classification in all hæmopathies.