﻿IX, B. 3 Boynton: Kidney-ivorm Infestation of Swine 273 



Several parietal thrombi were found in the branches of the 

 hepatic veins (Plate I, fig. 2, h). The largest one noticed 

 measured 1.9 centimeters in length, and filled approximately half 

 of the vessel. These thrombi are undoubtedly the principal 

 agents which cause the enormous passive congestion in the liver 

 by damming back the blood in the hepatic system. 



The walls of the main branch of the portal vein and vena cava 

 in some cases were considerably thickened, and possessed worm 

 tracts which were surrounded by fibrous connective tissue and 

 which contained worms or a mass of purulent material. These 

 worm tracts furthermore extended into the liver substance, re- 

 placing the parenchymatous with fibrous tissue. In 2 cases, large 

 accumulations of worm tracts were found in the regions where 

 the lobes join and on the posterior surface. Each of these 

 accumulations was surrounded by considerable connective tissue. 

 The largest of them measured 10.5 by 4.5 centimeters, and hence 

 extended a considerable distance into the liver substance. In the 

 immediate vicinity of these accumulations, isolated tracts were 

 found. The individual tracts varied from 1 to 2 millimeters in 

 diameter, and the walls were made of a gristlelike substance 

 which in turn was surrounded by connective tissue. 



KIDNEYS 



The kidneys like the liver showed a marked deviation from 

 the normal. A photograph of a kidney from pig A-18 is shown 

 in Plate I, fig. 3. This kidney measured 15.5 centimeters in 

 length and 6 centimeters in diameter. A retention cyst (Plate I, 

 fig. 3, a) was present on the external surface of the anterior end, 

 and measured 3 by 2 centimeters. It was somewhat triangular in 

 shape, the apex projecting toward the pelvis of the kidney. The 

 outer wall of the cyst was denuded of parenchymatous tissue, 

 was composed of tough, fibrous connective tissue, and was set 

 rather deep into the substance of the cortex. It is questionable 

 whether the worms were the cause of the cyst formation. How- 

 ever, retention cysts were present in the kidneys of 3 of the 

 6 hogs examined. Scattered over the surface of the kidney were 

 several uneven dark-purplish indentations, which were appar- 

 ently the scars of small healed abscesses. The surface of the 

 kidney was not uniform in color, but presented the appearance 

 of being injected with fine, irregular, reddish brown lines forming 

 a multitude of grayish brown blotches, averaging 1 millimeter 

 in diameter. The capsule of this kidney stripped easily. The 

 retention cyst contained a turbid semiviscid fluid. The internal 

 surface of the wall of the cyst was composed of smooth, fibrous 



