This photograph is another kidney, this time from a pig. The surface of this kidney has two different colors apparently one of them normal and one abnormal. I think probably the key issue here is the pattern in which the coloration exists. I can tell you that the darker red areas are abnormal. At 10 o'clock I think that they are not only red, they may also be raised and, if I were lucky, I might see some yellow specks within the red areas. This distribution is relevant to pathogenesis and seems to me there are two alternate pathogenetic mechanisms that might give a lesion of this distribution in the broad sense but really only one pathogenesis in the narrow sense. Think about it a little bit and then look at the next slide.
