Hypertrophy from chronic congestion, over feeding, hepatic cirrhosis.
In _horse_: from mechanical obstruction in heart, lungs, posterior
cava, splenic veins, angioma, from glanders or tubercle in lungs,
chronic splenic congestion, disease of splenic plexus. Lesions:
increase enormous; mainly of pulp, or largely of fibrous framework.
Special neoplasms. Symptoms: excess of leucocytes in blood,
eosinophile cells, weakness, anæmia, emaciation, bleeding from mucosæ,
stretching, right hypochondriac tenderness, stiff gait, ascites,
colic, disorder of the bowels, rectal exploration. Treatment: is that
of primary disease; not encouraging; quiniae, eucalyptus, saline
laxatives, open air, sunshine, electricity. In _cattle_ is habitually
enlarged in Texas fever area. In lymphadenoma increase mainly of
fibrous framework and Paccinian bodies, and of adjacent lymph glands.
Symptoms: leukæmia, employ palpation, percussion, rectal exploration.
Treatment as in the horse. In _swine_: from high feeding, leukæmia,
lymphadenoma, tuberculosis, neoplasms, liver, heart and lung disease.
Lesions: great increase of Paccinian bodies, fibrous capsule and
trabeculæ. In _dog_: from traumas, leukæmia and lymphadenoma. Enlarged
Paccinian bodies and adjacent lymph glands. Symptoms: leukæmia, many
eosinophile cells, abdominal enlargement, palpation, icterus.
Treatment: as for large animals.
A continuation of passive congestion from the causes enumerated above,
leads to permanent increase of the fibrous reticulum and connective
tissue and increase of the splenic pulp. Even the stimulus of a rich and
abundant alimentation increases the size of the whole organ, the amount
of pulp and the number and development of the Paccinian bodies. Apart
from disease the spleens of well fed cattle or horses are always
decidedly heavier than those of the starved or debilitated. Of
mechanical causes the most potent is cirrhosis of the liver or some
other obstacle to the free passage of blood through that organ. The most
common causes are, however, the continuous operation of those specific
poisons which determine the acute hyperæmias.