Amoebidae 89 



been cultured, but recent experiments indicate that some sort of tissue 

 extract in which the oxygen supply is kept constant will eventually be 

 successful. 



Miss Bonestell (working in this laboratory) has found that the various 

 species of Trichomonas multiply exceedingly rapidly in rat embryo ex- 

 tract, such as is used for tissue cultures. 



Bibliography 



Boeck, W. C.j and Drbohlav, J. 1925. The cultivation of Endamoeba histolytica. 



Amer. J. Hyg. 5:371. 

 Cleveland, L. R., and Collier, J. 1930. Various improvements in the cultivation 



of Entamoeba histolytica. Ibid. 12:606. 

 Craig, C. F. 1930. The cultivation of Endamoeba histolytica. In Hegner and 



Andrews: Problems and Methods of Research in Protozoology. 532+ ix pp. 



Macmillan Co., New York. 

 Deschiens, R. 1930. Culture de l'amibe dysenterique et nutrition de cette amibe 



dans les cultures. Extrait du ier Congres Internal, de Microbiol., Paris, pp. 1-4. 

 Dobell, C.| and Laidlaw, P. P. 1926. On the cultivation of Endamoeba histolytica 



and some other entozooic amoebae. Parasit. 18:283. 

 Kofoid, C. A., and Wagener, E. H. 1925. The behavior of Endamoeba dysenteriae 



in mixed cultures of bacteria. Univ. Calif. Publ. Zool. 28:127. 

 Kofoid, C. A., and McNeil, E. 1931. The advantages of Locke's blood medium 



in the culture of parasitic Protozoa of the digestive tract. Amer. J. Hyg. 



15:315- 

 St. John, J. H. 1932. A new medium for the culture of Endamoeba histolytica. 



Amer. J. Trop. Med. 12:301. 

 Tanabe, M., and Chiba, E. 1928. A new culture medium for Endamoeba 



histolytica. Acta Medicinalia in Keijo, 11 :i. 



IN VIVO CULTIVATION OF INTESTINAL PROTOZOA 

 IN PARASITE-FREE CHICKS* 



Robert Hegner, School of Hygiene and Public Health 



AS EVERY one who has attempted experiments with animal parasites 

 L in laboratory animals knows, one of the greatest difficulties is to 

 secure parasite-free animals for infection purposes. Chicks offer a num- 

 ber of advantages: they may be obtained at any time of the year; they 

 are very inexpensive; they are free from animal parasites when they 

 hatch from the egg; they may be maintained in the laboratory free 

 from animal parasites without difficulty and at low cost ; and they may 

 be inoculated very easily per os or per rectum with material containing 

 animal parasites. It seems evident that greater precautions are necessary 

 to prevent contamination under ordinary laboratory conditions with 

 Coccidia than with Amoebae, flagellates, or ciliates. 



Besides being parasite-free and easily maintained in this condition, 

 chicks are favorable for experimental studies because one may obtain 



* Reprinted from Science 69:432, 1929, with slight changes by the author. 



