pass cartridge and the syringe through a small bore to achieve mixing particularly in the case of microspheres held in suspension application_number US 46269609 A description referring to the drawings in greater detail and by reference characters thereto there is illustrated a mixing and transfer assembly generally designated by reference numeral 10 transfer and mixing assembly 10 includes a by pass cartridge generally designated by reference numeral 12 an outer housing about by pass cartridge 12 and generally designated by reference numeral 14 an activation cap 16 a plunger rod 18 a syringe 20 and a syringe plunger rod 22 by pass cartridge 12 has an outer wall 26 with a by pass 28 formed therein as is known in the art a septum 30 covers the outlet of by pass cartridge 12 and a cap 32 extends thereover mounted within by pass cartridge 12 is a rear plunger 34 which has a female luer fitting 36 an intermediate or middle plunger 38 is situated rearwardly of by pass 28 there is thus formed a rear compartment 40 which is defined as the space between wall 26 rear plunger 34 and intermediate plunger 38 a front compartment 42 is defined by wall 26 intermediate plunger 38 and septum 30 for most uses rear compartment 40 will contain the diluent while a front compartment 42 will contain the dry and.