Observations on the cellular activity in a culture of amphibian liver tissue.

Abstract

On January 2, 1924, two, very large, ameboid cells appeared in a culture of liver tissue, obtained from an adult Rana pipiens. This culture had been made on November 25, 1923, some five and one-half weeks earlier, and no cells had previously migrated into the clot. The culture was one of a series of twenty-five, and in none of the others was any cellular activity ever observed. The unusual size and activity of these cells, as well as their migration into the clot after the long inactive period of the tissue immediately commanded attention, and careful observations were made during the succeeding five days in which they retained their activity.

Each of the cell bodies was very irregular and constantly changing in shape, due to a flowing movement of the cytoplasm strikingly similar to that in an ameba. As a result of the cytoplasmic flow, cell processes of various lengths were continually formed at various regions of the periphery. When first observed each of the cells measured about 0.33 mm. in length. Later a maximum length of over 0.5 mm. was attained by one of the cells. The cytoplasm contained many granules of various sizes which moved into or out of the processes with the cytoplasmic current. After five days of continual activity in the clot, both cells rounded off, and each formed a somewhat spherical cell body which measured about 0.15 mm. in diameter. No further movement occurred in either of these cells although the culture was opened and one of them was isolated and placed in fresh medium in a subculture.

The identity of these cells is not clear, and so far as I am aware similar metazoan cells have not been described either in tissue cultures or elsewhere.