by the penetrating member 40 are seen in this view fig5 b shows an exploded view of an embodiment of a fluid connection between the interior of the drug reservoir as it enters the fluid passageway 42 and its conveyance to the cannula 44 referring now to fig6 a through 6 f the details of how the drug from the fluid passageway 42 flows through to the interior of the cannula 44 as the cannula is inserted into the body are shown in this embodiment the type of cannula used permits an insertion needle which in turn leads the cannula into its place and can be withdrawn the steps of this process serve to create the above mentioned fluid connection as follows fig6 a 6 b shows the overall arrangement of the cannula insertion mechanism and its fluid connection to the drug reservoir including an enlargement of the fluid connection as shown in the inserts in fig6 a and fig6 b in this aspect the piercing of the septum 28 by the first penetrating member 40 permits fluid exit from the drug reservoir 20 into the fluid passageway 42 fig6 c shows the initial state of the cannula insertion mechanism in which both the insertion needle 50 and cannula 44 are within the patch pump in this initial state the flow from the passageway 42 shown in fig6 b is blocked by a plastic sleeve 52 ensuring that none of the drug is lost until the cannula 44 has been inserted.