NEw York AGRICULTURAL EXPERIMENT STATION. 119 
type. Again Bact. 212.33300 includes Bact. lactis Conn and Bact. 
lactis viscosum. These two types are considered by Conn as dif- 
fering mainly in viscosity and this item does not enter into the 
group number but is recorded in the body of the Society card. In 
both of these cases it is possible that a determination of the nitrate 
reduction might remove the apparent conflict. 
On the other hand a type name according to Conn often includes 
germs answering to two or more group numbers. Thus M. lactis 
varians includes M. 211.22205; M. 211.22215 and M. 221.22205; 
M. lactis albidus includes M. 211.23200, M. 211.22200 and M. 221.- 
22200; Streptococcus lacticus includes Str. 212.22200 and Str.222.- 
22200; Bact. lactis acidi includes Bact. 212.22200, Bact. 222.22220 
and Bact. 222.22320; M. lactis aureus includes M. 212.22205 and 
M. 212.22305. An improvement in the details of the group number 
is desirable and will come, but even as it now stands the Society 
card system is a distinct advance over anything which has preceded 
it. 
CONCLUSIONS. 
The system of recording the reactions of cultures as proposed by 
the Society of American Bacteriologists is a marked advance in 
technique. By its aid the shifts in the cheese flora can be followed 
with more accuracy than was previously possible. The cultures 
isolated can readily be so characterized as to be recognized by suc- 
ceeding workers. Each investigator can thus build upon what has 
been done and a satisfactory acquaintance with such of the flora as 
will grow on our culture media is possible at no very remote date. 
The quantitative changes observed in nine normal cheeses, repre- 
senting four commercial factories and our own dairy, agree closely 
with those previously found in Wisconsin and Canada. Emphasis 
should be laid upon the fact that first class cheeses vary widely both 
in their total germ content and in the age at which the maximum 
number of bacteria is found. A parallel study- of the flora and of 
the commercial quality brought out the fact that at the time the 
cheese was commercially ripe it ordinarily contained some millions 
of living bacteria per gram. 
The qualitative study showed that the Bacterium lactis acidi of 
Leichmann is the only form which is constantly found in all of the 
cheddar cheese which has been studied. Representatives of this 
form are arranged under four different group numbers and it is 
highly probable that these groups mark distinct strains of Bacterium 
lactis acidi. 
