A STUDY OF FILTERABLE VIRUSES 



315 



with equal parts of physiological salt solution, pass it 

 through a clean, sterile, Chamberland filter at a pressure 

 not to exceed one atmosphere and 

 during a time not to exceed one 

 hour. 



3. Make sub-cultures of the fil- 

 trate by introducing 1 c.c. into each 

 of several flasks of bouillon contain- 

 ing 50 c.c. each. Take every pre- 

 caution against contamination. Also 

 make microscopical preparations. 



4. If no growth results under 2 

 inject 2 c.c. into the muscles of a 

 50 Ib. pig. Make daily observations 

 of the pig and record the temperature 

 each day, 



6. When undoubted symptoms 

 of hog cholera have developed, kill 

 the pig and make a careful autopsy. 

 Save the blood in a sterile jar. 



6. Repeat the experiment, using 

 blood procured in 4 as virus. 



7. By repeated nitrations and in- 

 jecting into susceptible hogs, it 

 may be proven that a living micro- 

 organism, incapable of producing visible growth in vitro, 

 passes through the filter and develops in the body of the 



pig- 



8. State your results and conclusions in full, 



FIG. 71. Pasteur-Cham- 

 berland Filter Adjusted 

 for Filtration by Suc- 

 tion. 



REFERENCES 



DORSET, MCBRYDE and NILES: Further Experiments Concerning 

 the Production of Immunity from Hog Cholera, Bui. 102, B. A. I., 

 U. S. Dept. Agr. 



MCBRYDE: Filtration Experiments with B. choleras swis, Bui. 113, 

 B. A. I., U. S. Dept. Agr. 



