Why when we cut onion tear come from our eye and when we cut onion chewing chemgun tear do not come from our eye

Why when we cut onion tear come from our eye and when we cut onion che

1.	Why when we cut onion tear come from our eye and when we cut onion chewing chemgun tear do not come from our eye
Answer» Why when we cut onion tear come from our eye and when we cut onion chewing chemgun tear do not come from our eye