Date of this Version
The effects of oxygen, carbon dioxide, and pressure on animal organisms have been widely studied, but most of the investigations in this field concern chiefly the effects of extreme, especially high, atmospheric pressures on blood changes, respiration, length of life, etc., in Vertebrates. Very few detailed observations have been made on the relation between oxygen tension or carbon dioxide tension and growth in Protozoa. The few investigations that have been carried out are concerned primarily with the effect of these gases on respiration although some observations have been made on the relation of aerobic and anaerobic conditions and growth in unicellular forms. Lwoff (1932) found that Glaucoma piriformis does not grow under anaerobic conditions, and Hall (1933) found that Colpidium campylum does not grow as well under anaerobic as under aerobic conditions. Jahn (1936) observed that Chilomonas paramecium grew best in unaerated culture flasks but that Glaucoma piriformis grew best in aerated flasks. The results of Phelps (1936) give support to those of Lwoff and ]ahn on Glaucoma piriforrais. Rottier (1936) maintained that inadequte amounts of oxygen limit the growth of Polytoma uvdla and Reich (1936) claimed that oxygen concentration is very important in cultures of Amoeba. Except for the work of Mast and Pace (1933) on the effects of carbon dioxide on growth in Chilomonas paramecium in inorganic solution, no observations have been made on the effect of various oxygen or carbon dioxide tensions on growth in unicellular forms. In the following pages, data concerned with the effects of different concentrations of these gases as well as the effects of total atmospheric pressure on unicellular organisms are presented.