For the first few days of cultivation of connective tissue in hypertonic, hypotonic, and diluted medium, cell proliferation was stimulated. The first outgrowths of new cells in the modified media did not occur sooner than in normal medium. In hypertonic medium the density of the area of cell proliferation appeared to be greater than the control, but in hypotonic or diluted medium there seemed to be no increase in actual mass over the control. These observations confirm the conclusions of Carrel and Burrows, as well as those of Lambert.
Subsequent to the first few days of cultivation in hypertonic medium the area of cell proliferation decreased and in a short time conditions developed which were unfavorable to growth, and finally resulted in death of the culture, unless it revived before this stage. Hypotonic medium after about ten days no longer caused more extensive areas of proliferating cells; but instead, the extent of new growth gradually decreased, and the culture merely remained alive unless revived. In diluted medium the extent of the area of cell proliferation remained greater with no actual increase in mass. The area of cell proliferation which is observed during the first few days in a culture of fresh tissue recently extirpated does not indicate the actual influence of modified media. It was only after continued cultivation of strains of connective tissue in these modified media that their influence on cell proliferation was determined.