Astanga Hrudaya
द्विवर्षां वा त्रिवर्षां वा शिशिरान्ते विशेषतः । तां पाटयित्वा शस्त्रेण क्षीरमुद्धारयेत् ततः ॥ ४५ ॥
A plant that is two or three years old should be selected. Especially at the end of the Śiśira (late winter) season, it should be incised with a sharp instrument to collect its milky latex (sap).
english translation
dvivarSAM vA trivarSAM vA zizirAnte vizeSataH । tAM pATayitvA zastreNa kSIramuddhArayet tataH ॥ 45 ॥
hk transliteration by Sanscript