a surgical instrument including an operative assembly and a supply assembly . the back of the operative assembly and the front of the supply assembly have complementary connectors forming a sealed connection between the assemblies . the supply assembly comprises at least one duct for feeding a first fluid as far as the connectors . the surgical instrument is characterized in that it comprises a member for sealing the fluid duct when the operative assembly is connected to the supply assembly , and the operative assembly includes a member for feeding at least one second fluid .