276 R. W. HEGNER. 



It was a surprise to find that paramecia are able to withstand 

 the digestive enzymes in the pitcher liquid. There may still 

 be some question as to whether these enzymes are produced by 

 the plant or by bacteria, but their presence is not generally 

 disputed by investigators. According to Dr. Edgar T. Wherry 

 (in letter) the pitcher liquid varies widely in reaction when the 

 hydrogen-ion concentration is measured so that the paramecia in 

 my experiments were probably living in solutions that differed 

 considerably in this respect. That paramecia are able to with- 

 stand conditions within the digestive tract of frogs has been 

 shown by Cleveland (MS). Rich cultures of paramecia were 

 injected into the rectum of living frogs; in some cases one or 

 less per cent, of them became encysted within usually from one 

 to 2 hours; the rest were killed. In one instance encystment 

 occurred within 30 minutes. 



So far as the problem is concerned that the experiments 

 described above were designed to solve, the conclusions seem 

 justified that, (i) paramecia are able to live within the liquid 

 either outside or within the pitchers of various ages borne by 

 vigorous plants for an indefinite period without injury; (2) 

 paramecia may multiply in the pitcher liquid; (3) colpoda and 

 chilomonas are similar to paramecia in these respects; (4) the 

 protozoa that occur in nature in the pitcher liquid are probably 

 free-living species carried there by flies although some of them 

 may be species restricted to this particular environment. 



LITERATURE CITED. 

 Hegner, R. W. 



'26 The Interrelations of Protozoa and the Utricles of Utricularia. BIOL. 



BULL. (In press.) 

 Hepburn, J. S. 



'22 Biochemical Observations on Certain Insectivorous Plants. Journ. 



Franklin Institute, 194: 771-781. 

 Hepburn, J. S., St. Johns, E. G., and Jones, F. M. 



'20 The Absorption of Nutrients and Allied Phenomena in the Pitchers of the 



Sarraceniaceac. Journ. Franklin Institute, 189: 147-184. 

 van Oye, P. 



'21 Zur Biologic du Kanne von Nepenthes melamphora. Biol. Centrlb., 41: 

 529-534- 



