Virya (potency) :—

Usna (heat) and sita (cold) being the powerful qualities,
v!rya (potency of the substances) is also taken to be two.
Notes :—--Virya is that aspect/factor of the substance which is mainly responsible for the actions of the substance in the human body. More details will be found in chapter 9.

Vipka (end product of digection) :—

Vipâka (nature of end product of digestion) is also three— sw.du (sweet), amla (sour) and ku (pungent). (17.)
Notes :——More details in chapter 9.

Gurvãdi guh (qualities) :—

Guru (heavy), mañda (slow), hima (cold), snigdha (unctous), 1aka (smooth), sãüdra (solid), rnrdu (sofr), sthira (stable), süksrna (minute, subtle) and viada (non-slimy)—these ten along with their respective opposites—are the twenty gunas (qualities, prope’ ties of substances).
Notes :—--The above statement can be elaborated as follows :—
Guru (heavy) x laghu (light in weight)
MaMa (slow) x tiksça (quick, fast)
Hima (cold) X usia (hct)
Snighda (unctous) x rãksa (dry)
lakça (smooth) x khara (rough)
Säñdra (solid) x drava (liquid)
Mrdu (soft) x kahjja (hard)
Sthira (stable) x cala (moving, unstable)
Sükma (subtle, small) x stbñla (big, gross)
Viada (non slimy) x picchila (slimy).



Hina (inadequate, poor), mithyã (improper, perverse) and ati (excess), yoga (association, contact, union) of kda (season), artha (objects of senses) and karma (activities, functions) are the chief causes of diseases; whereas their samyak yoga (proper contact, association) is the chief cause of health.