Torpid

torpid \ˈtor-pəd\ adjective: 1 a. having lost motion or the power of exertion or feeling; dormant, numb, b. sluggish in functioning or acting {a torpid frog} {a torpid mind},
2. lacking in energy or vigor; apathetic, dull

Etymology: Middle English, from Latin torpidus, from torpēre to be sluggish or numb

TWENTY — Engineers in Project Greensleeves ran a tube from the mouth back into the body (via the navel). The test subject inhaled through his nose and exhaled through his mouth, thus diverting carbon dioxide, the waste product of traditional cellular respiration, back into the body for use in photosynthesis. The solution was awkward, inelegant and prone to malfunction. Luckily a clever member of the respiration team discovered a switch in the lungs of all humans; when the switch was flipped the lungs suddenly began to work in reverse.