I30 



THE BACTERIAL CONTENT OF MILK 



of organisms both in good and bad milk during the first i68 hours. 

 At all the other temperatures, to which there is no exception, there 

 is a rise in the number of organisms. Secondly, the numbers of 

 bacteria at 20° C in forty-eight hours are equal to the numbers 

 at 35° C. in twenty-four hours, and in both instances the number 

 is phenomenally high. 



Our own examinations were made many times over, and in- 

 volved a considerable amount of labour. The results seemed of such 

 exceptional interest that the work was repeated on several occa- 

 sions. Briefly, it appears that the differences between our work and 

 Professor Park's is that we used i milk (instead of 2) ; that its 

 initial number of bacteria was 812,000 per c.c. (instead of 3000 and 

 30,000 per c.c.) ; that we worked at 3 temperatures only (instead of 

 10) ; that we carried out an examination at 18 periods (instead of 4) ; 

 and that in our experiment the organisms were counted up to thirty 

 days in regular sequence, and then at the end of two years. The 

 cultures were made in Petri dishes, but on gelatine instead of agar. 

 Other particulars will be found in the Notes following the table. 



The results were as follows : — 



* Milk turned distinctly sour. 



t At this stage the Oidium lactis, which had made its appearance on the 

 plates only rarely before, began to grow in profusion at the expense of other 

 organisms, which became slower in development. 



