go STORRS AGRICULTURAL EXPERIMENT STATION. 
red, anid one that was more difficult to distinguish from other 
types, particularly Group IV. Hence differentiation was con- 
siderably easier upon plates made from milk media than upon 
peptone plates. We next attempted to combine the media 
together for the purpose of obtaining, it possible, a medium 
that would give large numbers and at the same time a good 
differentiation. We used combinations of custard and peptone 
gelatin and of the whey and peptone gelatin, using half of 
each. ‘The two following tables represent the results of these 
experiments. These tables are given in part for the purpose 
of showing the value of different media and in part to show 
the limitations in the accuracy of the method of qualitative 
analysis as adopted in our laboratory. 
TABLE 15. 
Comparison of different culture media, given in percentages. 







di | | 
5 I pay ro 8 ome) 
go) gos | ee 
e | 6 |e ae 
a Ss & nS oH 
gE es 
Q ? 6 Bie 
Total number, - - | 195,500 | 216,700 | 217,000 | 241,000 | 231,500 
Slow liquefiers (Group VI. ae 5.3 ¥2,6 15.4 6.6 II.4 
Small lobed (micrococcus), — - 4.5 10.6 13.9 1 i | Thy 
No. 222 (Group VIII.), - - vig 14.2 B09 O8 ee 
Group IV., - - - r 60,3 31.8 8356 AA RE Se 
Group II.,_ - - - - .8 3.8 5.6 9 7.6 
Group, : < = - A. 53 ae 6.0 OF Ons 
EOD SV es he 2.6 ie Fires) 2.5 I.4 
Rapid liquefiers (Group * VI. 7 Ti5 .9 2.5 17 1.8% 
Group III., - - - — 2 2 — — 
Miscellaneous, ING. "ie 7 SO, Crna 4.0 ela ey 
Miscellaneous, No. 4, - - ats ae —_ — — 
Miscellaneous, No. 5, -: - 5.9 6.4 Ay 6.4 6.0 
Miscellaneous, No. 6, - - 25 — — os — 
Undetermined, RS s — On? ae 4.4 6.6 




From these tables it is seen that a combination of peptone 
with the milk media produced results somewhat higher than — 
any of them alone. ‘he differentiation of the colonies was 
also found better in combinations of the different media than it 
was in the peptone alone, though no better than in the milk 
media alone. It will be seen also from the tables that there is 
in general a close similarity in the percentage of the different y 

