@Roronoa:
Hmm, I got the impression he was referring to the 'life force' of Kinemon's body.
[http://www.batoto.net/read/_/110672/one-piece_ch672_by_mangarule/
.](http://www.batoto.net/read/_/110672/one-piece_ch672_by_mangarule/10) He can't distinguish between the 'life forces' of the fish and Kinemon's torso because he was INSIDE the fish. Meaning; The life force of Kinemon's torso is really weak. But yeah, the phrasing is definitely ambiguous and it could be interpreted your way too. It doesn't really sit right that Haki depends on a person's body while moves like blue walk can be used even with varying body strength. This lead me to the first conclusion.
That's what I was thinking. Sanji may have said his haki was weak (tis vauge)since he couldn't tell the torso from fish. He didn't realize at thatmoment, but after he thoguht it and saw the shark that its because the torso was inside a shark so the readings of torso & Shark were on top of each other.
@Kubihige:
Seeing as how Ace could only control a certain type of fire (fire less hot than magma apparently), I think CC's gas fruit is more based on poisonous/hazardous gasses, so no controlling oxygen and the such.
I'm confused on the post, the first part seems as if comparing the fire and magma as flames. Sorry if thats not what you mean, but its how it comes across to me. They aren't really related, magma is related to earth more than flame.
Mamga is not a fire, its rock thats so hot its molten, it can create flames by the intense heat. Its like how Crocodile can use the drying aspect of sand to crumble down brick or wooden doors.
I agree that CC can't control the oxygen people breate but for different resons. But do like teh idea he can create only toxic gases.
Any logia can control what they produce but not ouside what they created. Ace can contol fire he creates from his body or is stated by a flame from him (like a spark hitting a house) but he wouldn't be able to control fire someone else created, say Uspp's Firebird Star, but he can counter it easily and it certainly won't harm him.
Its how Oda makes sure the loigas are not too over-powered. So CC can create gases but he can not control the oxygen that others breathe (as soem fans have said) so no, he can not draw out the air from Luffy's lungs. Instead he could create a gas that could replace the oxygen they breathe.