PROPERTIES OF BACTERIOLYSANTS 481 



at 1:9 and one at 1:5 and the eighth filtrate attacked two cul- 

 tures at 1:21 and two at 1:5. It is thus obvious that cultures 

 differ in "lysability" just as they vary in "agglutinability." 

 One Flexner strain was tested with forty-eight different bac- 

 teriolysants, and was lyscd by thirty-nine at a dilution of 1:21, 

 by three at a dilution of 1:9, by five at a dilution in 1 : 5 and was 

 not lysed at all by one. 



The bacteriolytic power of subsequent generations of a stool 

 filtrate, obtained by filtering a dysentery culture which had been 

 lysed by being in contact for twenty-four hours or more with a 

 stool filtrate, in some instances was the same, in others greater 

 and in others less than that of the original filtrate. The type 

 of dysenterj^ bacillus to which the original filtrate was added in 

 the preparation of these subsequent generations, apparently 

 did not affect the titre of the succeeding generation of filtrate. 

 Among four filtrates that were carried through three to six 

 generations and were always tested against the same organism, 

 two had the same titres of lysis after each transfer and two had 

 different titres, i.e., after one "passage" lytic action might be 

 increased and after another "passage" it might be decreased. 

 Among three filtrates that were carried three to ten generations 

 and were always tested against two or more organisms, the titre 

 of lysis in each generation remained the same for one organism 

 and was different (increased or decreased) for the others. 



Twelve first to sixth generation filtrates, the originals of which 

 were obtained from the stools of four dysentery patients, were 

 tested against the dysentery bacillus isolated from those pa- 

 tients' stools as well as against other strains of Bact. dysenteriae. 

 Four of these filtrates were more active against their own pa- 

 tient's organism than the other strains, four were less active and 

 four were equally active. 



The bacteriolytic power of filtrates that had become contami- 

 nated with stool or air organisms and were then refiltered, was 

 sometimes the same, sometimes greater and sometimes less than 

 that of the original filtrate. Among nine contaminanted fil- 

 trates that were refiltered three had increased lytic power, three 

 had decreased activity and in three the activity was unchanged. 



JOUBNALOr BACrSRIOLO]T, TOL. Til, NO. S 



