In order to see whether or not the liver of different species of animals possesses antigenicity and also to study the significance of senstization with visceral antigens, the visceral specificity of liver antiserum, and the possible visceral disturbances the author carried out serological study on different species of animals (dogs and rabbits) and obtained the following results. 1. The liver of different species of animals possesses antigenicity, aud the serum of the rabbit sensitized with dog liver extract shows a relative visceral specificity in the reaction in vitro between this serum and the extracts of various organs, blood, and serum of the dog. 2. In the blood as well as in various organ tissues of the rabbit sensitized by the extract of dog liver can be detected antibody (liver antibody) as to react with such sentitizing agents. 3. When the serum of the rabbit sensitized with dog liver extract is inoculated into a normal dog, it disturbs the function of the liver and neighboring abdominal organs. Moreover, such a serum accelerates the production of antibody to react especially with the antigen extracted from the dog liver and also it reveals a relative visceral specificity.