A Study of the B. coll Group. 
363 
used for immunisation (Table XXVI). The group reaction was strictly 
limited to types belonging to the B sub-group. Thus with a number of 
strains of sub-group A, C and D practically no deviation was obtained (Table 
XXVII). 
In the case of sub-group A it was found that by deviation tests non- 
lactose-fermenters and organisms which only fermented lactose after mutation 
could be classed along with the typical lactose-fermenting types. In sub- 
group B non-lactose-fermenters {B. paracolon types) and strains which 
developed lactose-fermenting mutants {B. coll mutabilis types) could not be 
identified with the lactose-fermenting types, I. e. the group action of an anti- 
serum to a lactose-fermenter was limited to those types which fermented 
lactose in primary culture. 
As a result of these serological findings some indication has been elicited 
of the biological grouping of the different cultural types of coliform 
bacilli. 
The results may be summarised as follows : 
In sub-group A (gas-forming, indol +, inosite — , gelatin — ) as 
determined by tests with antisera to types 1, 2, 3 and 4, there is a high 
degree of specificity of the agglutinin for the individual strain used for 
immunisation, but no evidence of specificity for the type, or group action 
towards other organisms of the sub-group ; there is a relative specificity of 
the complement- deviating immune body, as determined with antisera to 
types 1, 3 and 4, for the individual strain but not for the cultural type ; there 
is, however, a well-marked group reaction limited to strains of the sub-group 
irrespective of other cultural reactions (e.g. lactose, dulc^te, saccharose, inulin 
ferm9ntation, motility), and not extending to the B, C or D sub-groups, B. 
paratyphosus B, or B. proteus. 
In sub-group B, as determined by observations with antisera to types 1 
and 2, there is a more limited degree of specificity of agglutinating antisera 
for the individual strain but not complete specificity for the cultural type ; 
there is absence of relative specificity of the complement-deviating antibody 
(antiserum to type I) for the individual strain, and the group reaction, as fai- 
as my observations go in the case of the types tested, is limited to the lactose- 
fermenting types, and does not extend to the A, C or D sub-groups, the non- 
lactose-fermenting types, of the B sub-group, the types which only fermented 
lactose after mutation, B. paratypliostis B or B. proteus. 
While among the indol + , inosite — , gas + types lactose-fermentation 
appeared of no more significance than certain other reactions, in the case of 
the indol — inosite , gas -f types the lactose-fermenting types seemed to be 
separately grouped as apart from the non-lactose-fermenters and those which 
only fermented lactose after mutation. 
Also in the case of two types of non-lactose-fermenters of the B sub- 
group exact specificity of the agglutinin for the type or species was noted, 
