a simulated liver 90 is provided which may or may not be secured in place to the body cavity or one or more of the adjacent organs as mentioned previously the various organs can all be located within the body cavity as shown in fig2 while not all of the organs are visible in fig2 the lungs 52 54 the heart 62 the liver 90 the small intestines 76 and the colon 82 are all shown in their proper relative positions the various organs may be readily removed for explanatory purposes for example if a child is about to undergo an appendectomy the large intestine 82 and the small intestine 76 could be removed from the body cavity either completely or partially to expose the appendix 84 the nurse or doctor could then show the child how the appendix would be removed by cutting it off with a scissors it is also contemplated that the appendix 84 could be detachably secured to the end of the colon 82 by means of snap fastners or the like so that it would only be necessary for the doctor to unsnap the appendix for purposes of demonstration the various organs and the rib cage may be made from any suitable materials and the organs may be constructed from different colored materials to help distinguish them from each other it is obvious that various types of fastners could be utilized in lieu of snap fastners for example velcro fastners could be provided for securing the various organs to each other and to the wall of the body cavity while the invention has been particularly shown and described with reference to a preferred embodiment thereof it will be understood by those in the art.