In the anastomosed intestine after the resection, the digestion and the resorption would be disturbed not only by the mechanical irritation, but also by the ascent and the ectopical increase of the coli bacilli. And by the detention action of the increasing bacilli in the liver, the function of the liver would be damaged. On this conception investigation was made in calculating periodically the number of coli bacilli increasing in the portal vein, bile duct and in the systemic blood circulation of the grown-up rabbit. The results obtained are as follows: 1. The portalvein, common bile duct and the systemic blood circulation of a grown-up rabbit are physiologically sterile. 2. In the portal vein, the coli bacilli appear in about 30 minutes after the anastomosis of the resected intestine and increase gradually in moderately large number from 2 hours & a half to 3 hours, but afterwards they temporarily decrease slightly or hold the horizontal line and one week later reach the peak, then gradually decrease and come back to the normal state in 3 weeks. 3. In the common bile duct, the coli bacilli appear in about one hour after the operation, afterwards they show no tendency of increase and it is likely that they disappear almost in several hours. 4. The bacilli appear in the systemic circulation also in about one hour after the operation, and show no tendency of increase afterwards and seem to disappear within 3 hours. 5. From the results mentioned above it is understandable that the coli bacilli are resolved directly into the portal vein and reach the liver, where they are seized by a eertain mechanism and the liver plays the leading role on the eradication of the bacilli in the blood stream. 6. The coli bacilli which are resolved into the portal vein after the anastomosis of the resected intestine are occasionally able to enter, even though they are a very few, into the systemic circulation. 7. From the fact that the bacilli in the common bile duct are small in number and disappear early, though they increase in the intestine, it is considered that the bile is mainly infected with its descending route and its ascending infection is not important.