MALI.EIN 



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- 

 Serum luted Serum 



1-40 



Amount of 

 Test Fluid 



3 c. c. 



3 

 3 

 3 

 3 

 3 

 3 

 3 

 3 

 3 

 3 

 3 

 3 



Dilution 



I -100 



1-200 



1-300 



1-400 



I -500 



i-5oo 



1-800 



1-1,000 



1-1.200 



1-1,500 



1-2,000 



1-4,000 



1-8,000 



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 

 37" 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. 



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