"The term 'general economy' is perhaps not the best one to use. An 'open,' 'folded' or 'excessive' economy may be [better] terms. [...] In this regard, the general economy acknowledges the 'foldedness' of the system in its relationship to the outside" (74-5).
The footnote to the above on 75-6 sounds a lot like Bryant, where a system's boundaries are porous, both open and closed. This makes a clear distinction between in/out impossible and hence the fold. Nonetheless, the boundary exists and thereby differentiates between internal and external relations, between system and environment. It's like Morton's Rift earlier in the thread.