Abstract
1. The fate of the embryonal granule cells have been the object of the strenuous study and opinion is still divided. In order to pursue this problem by means of tissue culture, identification was attempted as the first step in this present report.
2. The most striking feature of the tissue culture of the cerebellar cortex of the kitten and pnppy younger than 3 weeks after birth is the tremendous migration of the small cells. Among the small cells in the cerebellar cortex of the animals in this stage, the internal granule cells, glial cells and the small cells of the cortex are considered besides the embryonal granule cells.
But from the facts as follows the majority of the small cells are considered to belong to the embryonal granular layer.
a) The embryonal granule cells which are observed in the cerebellar cortex pressed between the cover glass and slide glass look very much like the small cells migrated in the tissue culture of cerebellar cortex of young animals.
b) These small cells do not appear in the tissue culture of the cerebellar cortex of the animals mature enough to lose the embryonal granular layer.
c) The small cells which appear in the tissue culture of parts of the brain other than the cerebellar cortex can be identified with the oligodendroglia, immature oligodendroglia and indifferentiated cells. Some of them remain difficult to differentiate from the embryonal granule cells, but this is rather natural considering the entity of the embryonal granule cells.
d) The embryonal granule cells seen in the tissue culture correspond well to the cells which have been reported so far by several authors in silver impregnated preparations.
3. Discussion was made about the differentiation of the small cells from the oligodendroglia and other indifferentiated cells. Mention was made also on the internal granule cells cultivated in vitro.
