John Ackrill argued that Aristotelian bodies are conceptually promiscuous, since they fail to exemplify the modal relations that are expected to hold between their matter and their form. Although "potentially alive", organic bodies are bound to be ensouled, on pain of lacking the required potential; but to the extent that they are ensouled, they are already actually alive. It seems odd to claim that a body may lack (qua "potential") what it cannot help having (as necessarily enjoying life). This paper claims that the standard solution (which distinguishes an essentially ensouled body from its underlying inanimate substrate) falls short of the strong unity living beings display, given that nothing in them can be accidentally alive (De Anima 415b13). An alternative proposal is advanced, based on two distinctions Aristotle draws in his philosophical lexicon: (i) both matter and form have a claim to being called "nature"; (ii) formal nature may be found in its subject either (ii.a) in actuality or (ii.b) in potentiality (Met. 1015a18). It is argued that the characterization of organic bodies as "potentially alive" conforms to (ii.b), a pattern that helps explain the specific way in which bodies share in the organisms' life. Two possible instances of (ii.b) are finally considered by way of illustration.