elevating the blood of our inner animal

The sheep for the Tamid offering would be Shechted in the northern side of the Azarah. A Kohen had to collect its blood in a sanctified vessel and carry it to the Mizbeach. The blood would be applied to the north-east and south-west corners of the Mizbeach and the remaining blood would be poured on the base.
 
On a personal level, sacrifices represent the refining and elevating of our animalistic side, which is the source of our selfish drives, negative emotions and the pursuit of physical gratification.
 
The lifeforce (Nefesh) of the animal is its blood - כי הדם הוא הנפש. In addition to meaning soul, Nefesh can also mean desire. The boiling blood represents the Animalistic soul’s passionate desires for materialism.
 
The Animalistic soul itself is not intrinsically bad. Its strong desires can be harnessed and redirected in a positive way towards G-dliness. Through this we fulfil the directive of the Shema as explained by the sages, to love Hashem with both of our inclinations.
 
Draining the blood from the animal represents removing our passion and excitement from its expression in selfish, material desires.
 
Pouring the blood on the Mizbeach teaches us that our passionate desire and enthusiasm can and should be channelled towards the service of Hashem.