HOOD ON BACTERIA IN MILK. 



91 



Ji. Acidi Lncti. Number of germs found iv 1-40 c. c. of milk- containing formaldehyde. 



Time after inocula- 

 tion. 



Immediate 



1st hour 



2nd hour 



3rd hour 



1st day 



2nd day 



3rd day 



6th day 



9th day 



No form- 

 alde- 

 hyde. 



14 



40 



216 



2220 



34400 



133000 



179000 



700000 



1300000 



/)'. Typhosus. Number of germs found in 1-40 c. c. of milk containing formaldehyde . 



Time elapsing after 

 inoculation. 



Immediate. 



1st hour 



2nd hour . . . 



3rd hour 



1st day 



2nd day 



3rd day 



6th day 



9th day 



No form- 

 alde- 

 hyde. 



270 



40 



3900 



7440 



94000 



48000 



6700O 



95000 



140000 



Tt will be seen that the following deductions may be drawn from the 

 results as stated in the tables. 1. Formaldehyde when added to milk 

 in the |)ropoi'tion of 1:100 destroys the three <ierms used in the experi- 

 ments within three hours. 2. In the strength of 1:500 formaldehyde 

 destroys the lactic acid bacillus within two houps. The typhoid bacillus 

 is slightly more resistant and the colon bacillus still more resistant. 

 '5. In the strength of 1:1000 formaldehyde destroys the lactic acid 

 bacillus after three hours, the typhiod bacillus practically within the 

 same time, while the colon bacillus is somewhat more resistant. 4. In 

 the strength of 1:5000 formaldehyde destroys the lactic acid bacillus 

 within two hours, the typhoid bacillus within two days, while the colon 

 bacillus may persist a day longer. Practically all three of these bacilli 



