MALLEIN 169 



The method consists in the preparation of a test fluid from 

 a suitable culture of Bad. mallei to which is added the diluted 



serum. 



The "test-fluid" is prepared by washing the growth 

 from a 72 hour acid-agar culture by the aid of a sterile wire 

 loop into distilled water containing 0.85 per cent sodium 

 chloride and 0.5 per cent carbolic acid crystals. This suspen- 

 sion is then placed in a thermostat at 60° C. for two hours, 

 which kills the bacteria. Three cubic centimeters of the 

 "test-fluid" are placed in each of several small test-tubes. 

 With a sterile pipette, the diluted serum is added to the tubes 

 of test-fluid and thoroughly mixed. In making the different 

 dilutions, the amount of diluted serum to be used is readily 

 ascertained by the following table ; 



Dilution of Amount of Di-j Amount of 

 Serum luted vSerum Test Fluid 



Dilution 



3 c. 



3 

 3 

 o 

 3 



3 



Where dilutions greater than i-iooo are made, a serum 

 diluted 1-80 may be used to better advantage, unless the 

 pipette employed is very finely graduated. In this case the 

 amount of diluted serum for a certain dilution must be double 

 that indicated in the table. 



The mixture thus prepared is placed in an incubator at 

 ^7° C. for 24-30 hours. A temperature higher than 37° C. 

 interferes with the agglutination. 



The reaction consists of a layer of the agglutinated bac- 

 teria covering the entire convexity at the bottom of the tube. 



