The Small Intestine Meridian is known as the "Sorter of Pure From Impure".  It is the energy that helps us discern what is needed and what is rubbish in a mental, emotional and physical sense
The Five Elements in Nature
After Spring we move into the active time of Summer.  This is the energy of Fire, the time of activity, warmth, movement, growth and relationship.  Nature itself is moving, the plants are growing, animals are getting ready to produce young and things are busy.
Fire is our ability to have relationship, to feel safe, to feel in control, to be intimate, to have fun, to laugh and be excited.

Fire is the energy of the Heart Meridian - the King or Queen of the body's Kingdom.  If the Heart is unstable there is a feeling of anxiety and panic - the kingdom is out of control. 
Summer and Fire
In society this is when we are outside, gathering in groups, enjoying each other's company at parties.  Humans and plants flourish with the warmth of the sun.  There is an uplifted, joyful feeling and a sense of safety.

When there is no warmth - no Fire energy - the world is a gloomy and chilly place.
The Three Heater Meridian looks after the three burning spaces - the top, middle and bottom of our bodies  trunk area. 

It is our internal thermostat that looks after our emotional and physical temperature.
Fire is also the energy of the Heart Protector or Pericardium Meridian.  This is our ability to have connection to people, the energy that stands in front of our heart and shields us from hurt, like a warrior would protect a monarch.
Spring and Wood
Summer and Fire
Late Summer and Earth
Autumn and Metal
Winter and Water