OF THE ALIMENTARY TRACT 55 



peatedly confirmed and elaborated work of Boeck and 

 Drbohlav (1925), and Endainoeba histolytica is now 

 subject to laboratory growth and study in artificial 

 media, although not in pure culture free from bac- 

 teria. 



The medium used by Boeck and Drbohlav, as im- 

 proved by Drbohlav, is prepared as follows: 



Take four eggs, wash and brush with alcohol, break 

 into a sterile flask containing glass beads, add 50 cc. 

 of Locke's physiological solution and shake until the 

 mixture is well broken up. Slant in test tubes to 

 the length of 1 to 1% inches and coagulate by heat 

 in an inspissator at 70° C. Transfer to the auto- 

 clave and sterilize for 20 minutes at 15 pounds pres- 

 sure. Cover the solidified egg to a depth of about 

 1 cm. above the slant with a mixture of 1 part of 

 sterile inactivated human blood serum in 8 parts of 

 sterile Locke's solution. Instead of the blood serum 

 mixture 1% solution of crystallized egg albumin in 

 Locke's solution may be used. Either of these mix- 

 tures may be sterilized by passing through the Berke- 

 feld filter. Their sterility should be tested by inocu- 

 lation and incubation of bouillon tubes or agar plates. 



The Locke solution is made as follows: 



Distilled water, 1000 cc; NaCl, 9.0 gms.; CaCls, 

 0.2 gms.; KCl, 0.4 gms.; NaHCOs, 0.2 gms.; Glu- 

 cose, 2.5 gms. Sterilized either in the Arnold or 

 autoclave. 



The amoebae do not penetrate the solid medium 

 but occur in the sediment of the lower part of the 



