four trees. two species. two sets of pairs. first set. first graft. primary branch Pyrus
                                            betulifolia J. severed to Pyrus pyraster 19. severed. whip and tongue. equal angles.
                                            {scions interchanged} to pyraster 19. joined to betulifolia J. joined. cambium to
                                            cambium. bound and waxed. {taken} vascular tissues grow together. inosculation.
                                            second graft. betulifolia G. severed to pyraster 2. severed. whip and tongue. equal
                                            angles. {scions interchanged} to pyraster 2. joined to betulifolia G. joined. cambium
                                            to cambium. bound and waxed. {taken} vascular tissues grow together.
                                            inosculation. third graft. betulifolia I. severed. pyraster 15. severed. part removed.
                                            space emptied. whip and tongue. equal angles. to pyraster 15. joined to betulifolia I.
                                            cambium to cambium. bound and waxed. {taken} vascular tissues grow together.
                                            inosculation. pyraster 14. part removed. space emptied. time passes. fourth graft.
                                            {Pyrus betulifolia grafted branch J. Pyrus pyraster grafted branch 19.} betulifolia M.
                                            severed to pyraster 21. severed. whip and tongue. equal angles. {scions
                                            interchanged and returned to original trees} to pyraster 21. joined to betulifolia M.
                                            joined. cambium to cambium. bound and waxed. {taken} vascular tissues grow
                                            together. inosculation. fifth graft. betulifolia P. severed to pyraster 14. severed. whip
                                            and tongue. equal angles. {scions interchanged} to pyraster 14. joined to betulifolia
                                            P. joined. cambium to cambium. bound and waxed. {taken} vascular tissues grow
                                            together. inosculation. new growth betulifolia branches K.L.M.N.O.P.Q.R. new
                                            growth pyraster branches 20.21.22.23.24.25.26.27.28. space filled. time passes…