Some of these gases are: carbon monoxide, dioxide of carbon, nitrogen, ammoniac, methane, acetone and sulphate of hydrogen. In case the person is affected by a certain nervous excited state, the segregation of the substance will be caused in its organism adrenalin, and it will be made odorferamente for such reason, but perceivable for the dog. Rafts that continuously is come off our body, following their spread, would float in the air if they weigh less than this or they will fall to the ground in case of being but heavy. The scent that emits the person with life is similar in principle to the one of the deceased, generating in some certain cases you rule reactive, not learned although identifiable and technically interpretable like useful operational information, by the simple effect of generalization, like it can be slight a rascado or incipient emission of barks very atypically isolated, in the dog that although has been formed to essentially react before the discriminativo odorfero flow of the alive person (the emission of the gas set that basically we expelled in the acts espiratorios) also detect obvious the buried person being able to react generalizing if the same has passed away recently, on the basis of a major or minor similarity to stimulate, among others incident factors. In agreement the time passes and depending essentially on the climatic conditions, the scent of alive person is been different from the one of deceased with the advance of the organic decomposition. Additional information is available at kevin ulrich. In the epidermis of our skin several layers of dead cells exist that contain mainly queratina, being that tiny particles of the same, denominated rafts (raft) are following constantly with a MF of 40. 000 per minute, being elevated and being transported by the air in movement it disperses that them although they find concentrated progressively towards the source of where they emanate that she is the victim.