Editing The Canon of Medicine (section)

====III The Temperaments Belonging to Age====

''The Canon'' divides life into four "periods" and then subdivides the first period into five separate categories.

The following table is provided for the four periods of life:<ref name=Bakhtiar />{{rp|68}}
{| class="wikitable"
|-
! Period !! Title !! Name !! Year of Age
|-
| I || The Period of Growth|| Adolescence || Up to 30
|-
| II || The Prime of Life|| Period of beauty|| Up to 35 or 40
|-
| III || Elderly life|| Period of decline. Senescence.|| Up to about 60
|-
| IV || Decrepit Age|| Senility || To the end of life
|}

Avicenna says that the third period shows signs of decline in vigor and some decline in intellectual power. In the fourth period, both vigor and intelligence decline.

Avicenna divides the beginning stage of life in the following table, according to Oskar Cameron Gruner's edition of the ''Canon of Medicine'':<ref name=Bakhtiar />{{rp|69}}
{| class="wikitable"
|-
! Sub-division !! Name!! Distinctive Characters
|-
| First|| Infancy|| The period before the limbs are fitted for walking
|-
| Second|| Babyhood|| The period of formation of the teeth. Walking has been learnt, but is not steady. The gums are not full of teeth.
|-
| Third|| Childhood|| The body shows strength of movement. The teeth are fully out. Pollutions have not yet appeared
|-
| Fourth|| Juvenility. "Puberty"|| The period up to the development of hair on the face and pubes. Pollutions begin.
|-
| Fifth|| Youth|| The period up to the limit of growth of the body (to the beginning of adult life). Period of athletic power.
|}

Avicenna generalizes youth as having a "hot" temperament, but comments that there is controversy over which periods of youth are hotter. The general notion that youth are "hot" in temperament is due to youth's supposed relationship to members of the body that are hot. For example, blood was considered "hot" as was mentioned earlier, therefore youth is assumed to be hot partially due to blood being more "plentiful" and "thicker", according to Avicenna. Evidence for youth having an excess of blood is suggested by Avicenna's observation that nose bleeds are more frequent within youth. Other contributing factors are the youth's association with sperm and the consistency of their bile. Further description of youth in regards to heat and moisture is given with respect to sex, geographical location, and occupation. ''The Canon'' says, for example, that females are colder and more moist.<ref name=Bakhtiar />{{rp|69–74}}