New York AGRICULTURAL EXPERIMENT STATION. IIL 
to both the system of the Society of American Bacteriologists and 
that of Conn. All of the cultures thus studied are included in 33 
groups, each characterized by a group number, or in 22 types. 
While a long list of additional forms will undoubtedly be recog 
nized in future studies of this field it is believed that this list of 
33 groups includes those which will be most commonly found in 
normal cheddar cheese in New York State. The group number of 
these forms, their type name according to Conn and the number 
of the cheese from which they were isolated are given in Table 
XXVI. The period during which each form persisted in the 
cheese is also shown. This determination has been made in two 
slightly different ways and the results from each are given. The 
age of the cheese at the isolation of the culture whose group num- 
ber was determined is indicated by + . In some cases the dupli- 
cate cultures mentioned above were isolated later in the history 
of the cheese than the one whose group number is positively 
known. In such cases the date of isolation of the duplicate cul- 
ture is marked by 0. We have every reason to think that the 
results expressed in Table XXVI by o are reliable while those 
shown by + are established beyond question. 
It will be observed from this table that of the first 11 forms 
six are not recorded after the first day and the remaining five not 
after the second day. With a single exception each of these 
forms was found in but one of the nine cheeses. Under these 
circumstances it seems proper to consider these eleven groups 
as merely accidental members of the cheese flora, unsuited by 
nature to thrive in and exert an influence upon the ripening cheese. 
Of the remaining groups eleven were found in but a single cheese 
but they persisted there a sufficient length of time to suggest that 
they might reasonably be included in the flora of typical cheddar 
cheese. Their infrequency of occurrence, however, makes it plain 
that they are not absolutely necessary to the progress of normal 
ripening. 
Accordingly it is among the fourteen remaining groups that we 
must look for the portion of the cheese flora which exerts a marked 
influence upon the normal ripening processes. The important part 
played by the lactic organisms in the manufacture and early his- 
tory of the cheddar cheese has been discussed at length in Bulletin 
227. | 
The type Bact. lactis acidi makes up 99 per ct. or more of the 
flora of normal cheddar cheese in practically all cases. The rep- 
