New York Agricultural Experiment Station. 49 



fected cteese with the aim of finding the habits of the causal 

 organism. In all, a dozen infected cheeses have been made be- 

 side the appropriate controls. 



Of these, three were made at different times each with the ad- 

 dition of a half dozen plugs drawn from a cheese thoroughly 

 spotted with the trouble. These plugs were first rubbed to a 

 thin paste with water and then added to the vat before it was 

 set with the rennet. In each of these experimental cheeses the 

 spots which developed were so widely scattered that they would 

 have passed any but a very careful inspector, and these three 

 trials may be put down as failures as far as the production of 

 spots in the cheese is concerned. 



Seven cheeses were made with the addition of a culture of the 

 causal organism to the milk before adding the rennet, and these 

 likewise failed to produce more than a few red points scattered 

 through the mass of the cheese^ and as far as practical considera- 

 tions are concerned these can also be classed as a failure to pro- 

 duce anything approximating what is commercially known as 

 rusty spot. 



Two cheeses manufactured at different times and using cul- 

 tures derived from outbreaks in different factories were made by 

 adding a culture to the vat just after the curd had been cut. In 

 each case the interior of the uncolored cheese within ten days 

 was so abundantly filled with small red points that at first glance 

 these colored points seemed to blend and give the entire cheese a 

 high red color. 



While these observations are too few to be relied upon as prov- 

 ing anything regarding actual conditions in the factory they are 

 in many ways very suggestive. In the first place these experi- 

 ments show that a cheese may contain a large number of the 

 proper kind of germ and still not show any discoloration. This 

 may throw some light upon the failure of the spots to appear in 

 the make of certain days in an infected factory. 



Again, these results suggest that the stage of the process when 

 the germs enter the vat may be very important. When the milk 

 ifi curdled by the rennet all these minute plants within the mass 

 4 



