[The nucleus cervicalis lateralis in sheep].

The objective of the work was to determine: a) the presence of the nucleus cervicalis lateralis in the sheep, b) the extent of this nucleus in the spinal cord and medulla oblongata, and c)the number and size of its cells. The histological method of staining the nerve tissue with methylene blue according to Nissl was employed. The nucleus cervicalis lateralis of the sheep is situated in the lateral funiculus, in the caudal part of the medulla oblongata and in the first three cervical segments of the spinal cord. The total number of cells making up the studied nucleus was 1629 in sheep I, 678 in sheep II, and 732 in sheep III. The average size of the cells ranged between 18.0 and 28.0 mu. In comparison with the same nucleus examined in other animals, that of the sheep shows a number of cell-free areas. It is composed of a very small number of cells, whose average diameter is small. These characteristics make it possible to regard the nucleus cervicalis lateralis in the sheep as a rudimentary structure.