While the trichromatic theory makes clear some of the processes involved in how we see color, it does not explain all aspects of color vision. The opponent-process theory of color vision was developed by Ewald Hering, who noted that there are some color combinations that people simply never see. For example, while we often see greenish-blue or blueish-reds, we do not see reddish-green or yellowish-blue.
Spay and Neuter Average Costs. The average costs of a spay or neutering procedure is $100 or $ 150. However, the costs of the surgery may be anywhere between $50 and $500.The price may depend on several factors including: 1  The method used for the spaying; presently there are 2 methods employed: the traditional method using a scalpel and the laser beam procedure. The method used for the spaying; presently there are 2 methods employed: the traditional method using a scalpel and the laser beam procedure. 2  The laser neutering procedure is costlier than the traditional surgery. 3  The location of the clinic may also be a factor that influences the costs.
How Much Does it Cost to Spay a Cat? While the cost to spay a cat varies, the operation typically runs from $300 to $500 for a female cat and around $200 for a male when itâs done at a private, full-service veterinary practice, said Cory Smith, spokeswoman for The Humane Society of the United States. Fortunately, there are less expensive options. For a fraction of the cost, cat owners can have the surgery performed by a non-profit spay/neuter service. These services typically cost around $50, and can be higher or lower depending on where you live.