Of this sort is the illusory sense of temperature which we often experience through a special state of the organ employed.
While there are these errors of interpretation due to some peculiarity of the organization, there are others which involve no such peculiarity, but arise through the special character or exceptional conformation of the environment at the moment.

Of this order are the illusions connected with the reflection of light and sound.

We may, perhaps, distinguish the first sub-class as organically conditioned illusions, and the second as extra-organically determined illusions.

It may be added that the latter are roughly describable as common illusions.

They thus answer in a measure to the first variety of organically conditioned illusions, namely, those connected with the limits of sensibility.