306 



STATE BOARD OF AGRICULTURE. 



SAMPLE I. 



Hours after milking. 



0... 

 15i.. 

 20^.. 

 40§.. 



Acidity of 

 sample. 



16° 

 10° 

 16° 

 16° 



87° 



Total number 

 of bacteria. 



530 



49,500 



275,000 



09,000,000 



2,000,000,000 



Otj 







2 





 







2 



2 



36 



1100 



* Should be read horizontally only and not vertically. 



tWhen zero appears it means that no colonies of that type could be determined, or for some reason 

 were not determined. 



jSince there was no appearance of any change in this sample, twenty -four hours was allowed to 

 elapse. This was a mistake in judgment, for there ought to have been some record between 40J 

 hours and 64J hours — the milk was loppered at 64i hours. 



COMBINATION la AND Ij. 



Dilutions employed for inoculating milk flasks. 



Culture la 1 : 100,000,000 



Culture Ij 1 : 100,000,000 



Number of bacteria la, introduced into milk flask la =4. 



Number of bacteria, Ij, introduced into milk flask Ij = 6. 



Number of bacteria, la and Ij, introduced into milk flask la + Ij ^ 4 + 6 = 10. 



Changes in milk flasks apparent to eye. 



Milk flask cultures prepared Wednesday, 3 p. m. 

 42 hours after inoculation, Friday, 9 a. m. 



la — no change. 



la + I j— litmus red. 



Ij — litmus red. 

 53 hours after inoculation, Friday, 8 p. m. 



la — no change. 



la + Ij — loppered. 



Ij — litmus reddened; no lopper. 

 65 hours after inoculation, Saturday, 8 a. m. 



la — no change. 



la + Ij — loppered. 



Ij — loppered more firmly. 



Acid developed during changes. 

 Time after inoculation. 



Culture la 



Culture la + Ij 



Culture Ij 



Bacterial Counts. 

 In 53 hours. 



Culture la— 300,000,000. 

 Culture la + Ij— 2,900,000,000. 

 Culture Ij— 1,000,000,000. 

 (In the combined culture, la + Ij, many of la were still visible, perhaps 500,000,000.) 



COMBINATION lb AND Ij. 



Dilutions employed for inoculating milk flasks. 



Culture lb I : 1,000,000 



Culture Ij 1 : 100,000,000 



Number of bacteria, lb, introduced into milk flask lb = 20. 



Number of bacteria, Ij, introduced into milk flask Ij = 9. 



Number of bacteria, lb and Ij, introduced into milk flask lb + Ij = 20 + 9. = 29. 



