296 SELLARDS. 



of immune bodies , would be those in which infection of the liver with 

 abscess formation has occurred. However, one would not expect to find 

 very active sera in view of the low grade of immunity in protozoan 

 infections generally and because of the comparatively slight response of 

 animals to the injections of amoeba. 



Samples of sera were taken in the stage of active dysentery, during 

 convalescence, and after recoveryj the majority of cases having been treated 

 with ipecac. The diagnosis of the cases was based upon the presence of 

 a dysentery resembling the usual course of the amoebic type together with 

 the finding of amoebae miscroscopically in the stools. No cases were avail- 

 able in which spontaneous recovery took place, although some had ex- 

 perienced repeated relapses alternating with periods of several months in 

 which no symptoms were present. 



The sera from these cases were tested against the 4 races of aincebae. 

 As a routine, the serum was used in dilutions of 1 to 2, 1 to 5, 1 to 10, 

 1 to 20, 1 to 50, and 1 to 100, the final readings being made after 18 

 to 24 hours. In the first case which was 'tested, the sample of serum was 

 taken 4 days after the subsidence of an acute attack of dysentery. A 

 definite reaction took place at 1 to 2 dilution with Eace A, the amoebaa 

 obtained from the city water supply. The preparations in the other 

 dilutions and with all of the other amceb* behaved like the controls 

 prepared with normal serum. In a repetition of this test 4 days later, 

 no reaction was obtained in any dilution with any of the 4 races of 

 amoebae. The second patient who was examined had exhibited symptoms 

 of chronic dysentery for many months. The serum from this case re- 

 acted only in 1 to 2 dilution with Eace B, the amoebae cultivated from 

 the stools of a dysenteric patient. All of the other preparations showed 

 no lysis. There was no opportunity for confirming this result. The 

 remaining cases that were examined consisted of 5 acute cases, 8 chronic 

 ones, and 3 with liver abscess. The acute cases were examined while the 

 symptoms were active and also within two to four weeks after recovery. 

 None of these reacted with any of the races of amoebae that were tested. 

 The 8 chronic cases were examined during a period of relapse and 5 of 

 these were also tested at a later period when they were free from symp- 

 toms. All, however, reacted like the normal control sera, the amoebae 

 remaining numerous and active in the 1 to 2 preparations and in all of 

 the higher dilutions. Of the 3 cases of amoebic abscess of the liver, one 

 was tested 4 days before exitus and the other two were tested at operation 

 and after recovery. The sera of these cases produced no lysis with any 

 of the cultures of amoebae, and these cultures failed to agglutinate with 

 the sera from the human cases. . 



From the behavior of these tests, it seems probable that the reactions 

 obtained in the first 2 cases were merely accidental. The reaction re- 

 sulted in one case with amoebae secured from a well-protected river- water,- 



