अग्नौ प्रक्षिप्तं चिटचिटायत् इन्द्रधनुर :

अग्नौ प्रक्षिप्तं चिटचिटायत् इन्द्रधनुर ( agnau prakṣiptaṁ ciṭaciṭāyat indradhanurvaṇaṁ vā )
Meaning: In cases of poisoning, a piece taken from the heart and thrown in fire produces a crackling sound and becomes rainbow colored, he should hold that as poisoned.