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Scientific Proceedings (131) 



The young worms were recovered from the liver on the third 

 day. This was as early as they were recovered from the pleural 

 cavity and was one day before they were found in the peritoneal 

 cavity. They were never found in the pleural or peritoneal 

 cavity in large numbers, except in one rabbit, which showed the 

 lesions of chronic passive congestion of the lungs and other 

 viscera. The pleural cavity of this rabbit yielded 171 young 

 worms while in the peritoneal cavity only one worm was found. 



In these rabbits petechial hemorrhages were numerous in the 

 lungs from the second day on. They appeared in the mucosa of 

 the stomach and intestine on the third day, and in the muscles, 

 the deeper layers of the skin and most of the other viscera on 

 the fourth day. On the fifth day they were intense in all the 

 viscera' but thereafter became progressively fewer. Serial micro- 

 scopic sections through a hemorrhage in the gastric mucosa and 

 through the cortex of one kidney of a four-day rabbit, showed 

 young worms in both localities. 



A series of four mice was killed on the fourth to the seventh 

 day after infection. Serial microscopic sections of one lobe of 

 the liver of the four-day mouse showed that even this early the 

 worms were all in blood vessels. Most of the blood vessels con- 

 taining worms could be identified as portal veins. Possibly the 

 remainder were also portal veins, but no bile duct could be seen 

 accompanying them. The worms were distributed evenly 

 throughout the liver. There was no tissue reaction or hemor- 

 rhage in the liver such as there was in other organs. The 

 diaphragm of each of these four mice was sectioned serially. 

 The only worms found were one on the fourth day and two on 

 the seventh. The pleural cavity in these mice showed worms 

 on the fourth, fifth and sixth days. The peritoneal cavity 

 showed no worms in any of these mice. 



As a result of these experiments we conclude that the prin- 

 cipal route of migration of Schistosoma japonicum from the 

 lungs to the liver is by way of the pulmonary veins, aorta, me- 

 senteric arteries and mesenteric and portal veins. 



