1 14 AGGLUTINATION 



this purpose, it is very specific, as group reactions almost never take place. 

 Strong agglutinating sera are easily obtained by immunization of animals. 



3. Epidemic, Cerebrospinal Meningitis. Agglutination in this disease 

 serves mainly for the identification of suspicious meningococcus cultures. 

 As has been shown by Wassermann and Kutscher, some strains are agglu- 

 tinated only after a long period (twenty-four hours) and at higher tempera- 

 tures as 56 C. 1 



4. Dysentery. The agglutination property is employed both for testing 

 the serum, and identifying cultures. The Flexner type of bacillus pro- 

 duces agglutinins more readily than the Shiga-Kruse. It is also- 

 agglutinated more readily. Only positive reactions in dilutions of i : 30 

 are of diagnostic consideration. Occasionally, partial agglutination takes 

 place with heterologous dysentery strains, typhoid and colon bacteria. 



5. Pest. The reaction is very specific, but of slight significance, as it appears only 

 on the ninth day; occurring with a serum dilution of 1:3, it is considered of positive 

 diagnostic value. 



6. Malta Fever. In most instances the serum gives the agglutination reaction with 

 the micrococcus melitensis. Normal serum may give the reaction in dilution i : 30, 

 so that higher dilutions only are of aid in diagnosis. 



7. Staphylo-, Strepto- and Pneumococci. Clinically, the agglutination test is never 

 employed in these cases. 



8. Tuberculosis. Here the agglutination test is associated with the difficulty of 

 obtaining a homogeneous tubercle bacillus suspension. This, however, is overcome 

 in one of two ways. 



a. Arloing-Courmont's Method (1898). The tubercle bacilli are obtained in the so- 

 called "homogeneous culture" form. S. Arloing first grows the bacteria on potatoes 

 for a long time, and then transplants them in glycerin bouillon which is shaken 

 daily for five minutes. After a number of subcultivations, a culture is obtained after 

 several months. This strain grows rapidly in a few days and diffusely clouds the broth. 



Such a culture diluted with physiological saline solution is used for the test. Here 

 small test-tubes are preferable and the ingredients should be mixed in the following 

 proportions: 



2 drops of serum -f 10 drops of culture (i : 5) 

 i drop of serum -f-io drops of culture (i: 10) 

 i drop of serum +15 drops of culture (i: 15), etc. 



The tubes are well shaken and placed in the incubator. According to Arloing 

 and Courmont, a positive reaction even in the dilution of i : 5 speaks for tuberculosis. 

 Best results are by this means obtained in incipient and mild tubercular cases; those 

 which are farther advanced do not react. 



b. Method of Koch. Koch niters the ordinary tubercle bacillus bouillon cultures, 

 dries the remnants upon the filter, and rubs them up in an agate mortar with N/5o 

 NaOH to a dilution of 1:100. The solution is centrifugalized and enough weak 

 HC1 is added until the reaction is only slightly alkaline. The dilution is then brought 



1 Frequently, during even the first days of the disease, the patient's serum in a dilution of 

 i- 10 gives the agglutination test. This is rare with higher dilutions of the serum as 1-50. It 

 usually takes some time before the agglutination becomes evident. \ 



