Morphological studies on lyssa in cats and dogs

The aim of this study is to reveal the morphology of the lyssa in the cat and dog. Eight heads of adult healthy cats and eight heads of dogs of both sexes were used as materials. In the cat the lyssa, yellow coloured, had a helical appearance and its edge facing the oral cavity became sharp; in the dog the lyssa, pinkish white coloured, was more or less J-shaped. The whole body of the cat's lyssa was buried among the intrinsic lingual muscles. In the dog, although aboral, two thirds of the lyssa were squeezed among the intrinsic lingual muscles, its cranial third was placed just under the mucosa to protrude slightly into the oral cavity. In both species, the whole body of the lyssa was determined to have been formed by the nearly adipose tissue in which occasional striated muscles existed. Moreover, in the middle third of the dog's lyssa, dense striated muscle fibres were seen dorsally to the adipose tissue, and we also noticed with interest that the lyssa sheath embracing this part contained few muscle spindle-like structures. It was of interest that in the cat a pyramidal rod encircled by a fine capsule of connective tissue was attached to the ventral edge of the cranial third of the lyssa.