CHRONIC ANÆMIA. DROPSY IN CATTLE AND SHEEP.
Definition. Causes, parasitic and microbian. Symptoms. Treatment.
Definition. A progressive anæmia in ruminants and other animals, resulting in general anasarca, and dropsies of the internal cavities.
In veterinary works published on the European Continent this affection is given a special place apart from the same train of symptoms which mark distomatosis, taeniasis, and strongyliasis. The disease is described as prevailing in wet years, after inundations, when the vegetation is rank and aqueous, and of course largely aquatic, in animals that are turned out in early morning before the dew has evaporated, in the conditions, in other words, that favor the ingestion of parasites. It prevails also in work oxen fed on the refuse of sugar factories (beets, turnips) in which the nitrogenous materials are held to be deficient, but in Great Britain where cattle are often fattened on an exclusive diet of turnips, containing even a larger proportion of water, this non-parasitic disease is unknown. It is also ascribed to close, ill-ventilated, unwholesome buildings, and to over-kept and tainted fodder, and so far as a separate disease exists, it seems more reasonable to charge it to the toxins produced by bacterial ferments or cryptogams than to causes which elsewhere appear to be inoperative.
The symptoms are essentially those of distomatosis, and the treatment, apart from the parasiticides, is the same. When helminthiasis can be certainly excluded prevention would include the avoidance of the factory refuse, especially when in a state of decay.
MELANÆMIA. BLACK PIGMENT IN BLOOD.
Definition. Melanin, in normal tissues, abnormal. Melanosis. Bisulphide of carbon subcutem. Decomposition of hæmoglobin in leucocytes. Coloration of tissue.
Definition. Accumulation of granules and scales of blood pigment (melanin) in the circulating fluid, and in various organs (spleen, liver, bone marrow, brain, etc).
Melanin—C44.2, H3, N9.9, O42.6—or black pigment (a close relative of hæmatin) occurs physiologically in epithelium (choroid, retina, iris, in the deeper layers of epidermis, and on the surface of the dog’s lung and of the sheep’s brain) and in connective tissue corpuscles (lamina fusca of the choroid).
Pathologically it is found in the blood of the victims of malarious fever, often in great abundance, and in the spleen, liver, bone marrow, brain, lymph glands and some other organs. It is formed abundantly in the black pigment tumors (melanosis) of man and animals, and in extensive melanosis is present in the blood of both man and horse (Schimmeln). So far it has not been found in connection with the extensive destruction of red globules which takes place in anæmia. Schwalbe has developed malanæmia experimentally by the hypodermic injection of bisulphide of carbon in rabbits.