This affection is occasionally seen among dogs in early life. The formation of tubercules on the membranes of the brain, is generally stated to be the exciting cause; the normal fluid contents become intensely augmented, and portions of the brain degenerate and soften. The affection is more often present at birth, but is not necessarily congenital. A state of impaired nutrition, a weakly constitution, and the co-existence of rickets or scrofula is the more often noted.

Puppies affected with the disorder show a lack, and possibly a total absence of intelligence. Very often partial paralysis of the hind legs occurs, and the dull, drowsy, symptoms observed in compression manifest themselves in a greater or less degree. Convulsions often set in late in the disease. The general appearance of the animals after a time clearly indicates the hopelessness of treatment.