T H E EFFECTS OF THE DILUTION OF THE MEDIUM ON THE GROWTH OF THE SPLEEN.* By ALEXIS CARREL AND MONTROSE T. BURROWS

Since the appearance of the work of Jacques Loeb, it is well known that the rate of growth of certain marine organisms is markedly influenced by the physicochemical conditions of the water. In alkaline sea-water, the fertilized eggs of the sea-urchin develop more quickly than in normal sea-water. When tubularia are deposited in hypotonic sea-water, their growth is considerably increased. The experiments of Loeb have demonstrated the extreme sensitiveness of living cells to variations in concentration of the hydroxyl and hydrogen ions, and the importance of the osmotic tension of the water for the growth of the organisms. The growth of the tissues of mammals is probably controlled by the conditions of the interstitial lymph in the same way that the growth of the egg of the sea-urchin is influenced by the conditions of the water. The organic and inorganic components of the blood are doubtless the most important of the physicochemical mechanisms which regulate the growth of the body. Therefore it may be assumed that the facts discovered by Loeb in the lower marine organisms are the expressions of general laws which control the development of the tissues and organs of the higher animals as well. Since the tissues, in their development, must adapt themselves to the morphological plan of the organism, their growth must be con-