ते ह नासिक्यं प्राणमुद्गीथमुपासांचक्रिरे तं हासुराः पाप्मना विविधुस्तस्मात्तेनोभयं जिघ्रति सुरभि च दुर्गन्धि च पाप्मना ह्येष विद्धः ॥ १.२.२ ॥
In plain words
They worshipped the breath in the nose as the Udgītha. The demons pierced it with evil; and therefore with it one smells both what is fragrant and what is foul, for it has been pierced with evil.