THE AGGLUTINATION REACTION 305 



the agglutinoscope (Fig. 87). The tubes are placed in a rack having 

 numbered holes, and are viewed from beneath with the aid of a mirror. 

 In this way one looks upward through the column of fluid, and secures a 

 combined view of sediment and turbidity, and when examined with the 

 culture control, fine and accurate readings may be made. 



The method of Kolle and Pfeiffer is very convenient, and may be 

 safer than that of adding live cultures with a pipet. It is conducted as 

 follows : 



1. Make dilutions of serum as described. 



2. Emulsify thoroughly a loopful (2 mg.) of culture from an eighteen- 

 to twenty-four-hours-old agar culture in the first test-tube, repeating 

 the process in the second tube, and so on through the series. In this 

 method the serum dilutions are not doubled ; thus in the foregoing series 

 the dilutions would be 1 : 10, 1 : 20, 1 : 40, 1 : 80, 1 : 160, 1 : 320. 



3. The tubes are gently shaken, labeled, plugged, and incubated as 

 directed in the preceding method. 



Oxford University Method. This technic is very serviceable in 

 routine examinations in the diagnosis of typhoid and paratyphoid fever. 



Take a stand containing 15 agglutination tubes in 3 rows of 5 each, 

 and a dilution tube. 



With the proper dropping pipet measure out into the dilution tube 

 54 drops of normal saline solution, 0.85 per cent, sodium chlorid, in 

 distilled water (where the water supply is pure, tap-water can be used 

 instead of saline solution) by means of gentle pressure on the teat. 



Wash the pipet with distilled water. 



Dry out the pipet with successive quantities of absolute alcohol, 

 followed by successive quantities of ether, and get rid of the ether. 



Take up the serum to be tested into the dried pipet. Measure out 6 

 drops of the serum into the dilution tube already containing the 54 drops 

 of saline solution, thus obtaining a dilution of 1 in 10. Mix thoroughly. 



Carefully wash out the pipet. 



With the pipet measure out into each row of tubes as follows: 



Drops of Drops of 

 Normal Serum 



Number Saline Dilution 



of Tube. Solution. 1 in 10. 



10 



2 



3 8 



4 9 



5 10 



To each tube in row 1 add 15 drops of 

 B. Typhosus Culture. 



To each tube in row 2 add 15 drops of 

 B. Paratyphosus A. Culture. 



To each tube in row 3 add 15 drops of 

 B. Paratyphosus B. Culture. 



20 



