After inducing experimental liver injury in normal adult rabbits by the injection of chloroform, carbon tetrachloride, or allyl-formate the relationship between the mesobiliviolin reaction at the time when urinary urobilinogen is positive and the results of various examinations on liver function was studied simultaneously, and the following results were obtained. 1. There is found no proportional relation between the concentration of urinary urobilinogen and the positivity of mesobiliviolin reaction, and when urobilinogen is at normal level, the mesobiliviolin reaction proves to be always negative. 2. The histological pictures of the liver when it is mesobiliviolin positive reveal a strong stellate reaction, showing a marked correlation, but there is not necessarily their correlation with the degree of liver cell degeneration. 3. At the time when mesobiliviolin reaction is positive, Takata's reaction and CCF give the rate of 94.1% and 88.2% respectively, showing a marked correlation with one another. TTT gives the rate of 64.4%, being somewhat lower, but there can be observed no correlation between the serum bilirubin level and the positivity to the mesobiliviolin reaction. The degree of BSP injury is 82.3%, showing a good correlation. On the other hand, between the urinary urobilinogen content and these liver functions there is no appreciable correlation. 4. Therefore, even assuming that mesobilirubinogen is disposed of by the liver endothelial system, it represents a more marked injury of the liver than urobilinogen.