10 



from pasteurized cream, was divided into several lots —one 

 for each preservative tested. The small lot of fresh 



butter was taken from the large "Success" churn and placed in a small 

 Simplex churn for working-. After placing- the butter in the churn the 

 preservative was sifted over the butter, and distributed as evenly as pos- 

 sible. The worker attachment was then put in motion and the butter was 

 given the usual amount of working— 18 to 19 revolutions of the worker. 

 In those experiments where salt was used with the preservative, the two 

 were weighed separately and then thoroughly mixed before adding them 

 to the butter. All the different preservatives were plainly labelled and 

 after weighing were placed on papers marked with the name of the pre- 

 servative. The boxes and prints were numbered at the time and a record 

 made of the preservative together with the distinguishing number so that 

 there could be no mistake and no mixing of the different lots. Every 

 known precaution was taken that each lot should contain the preserva-, 

 tive intended for it and no other. In all the summer eApenments, one 

 pound print wrapped in parchment paper, and one 28 lb. box were mark- 

 ed and placed in the refrigerator for scoring. The boxes were lined with 

 heavy parchment paper which had been previously soaked for at least 24 

 hours in a brine and formalin solution. Every precaution was taken to 

 prevent mould or unnecessary deterioration of the butter. Four lots were 

 made from ripened cream and two from sweet cream. In all cases the 

 cream had been previously pasteurized at a temperature of 180 to 185 

 degrees F. 



The Preservatives. 



The commercial preservatives were secured from the different firm^ 

 or their agents. We wrote all the Canadian firms whom we could heai^ 

 of as selling goods of this class in Canada. We explained the nature of 

 the work we intended doing and asked them to send us a sample of their 

 regular goods. Most of the firms cheerfully donated sufficient for our 

 work. The borax, boracic acid and sodium fluoride were purchased from 

 chemists. The salt was a portion of that from our regular supply. 



Each of these preserving substances was submitted to a close chemical 

 examination, the results of which are given below. The number of the 

 chemical preservatives will be used to designate these substances here- 

 after. 



No. 1 Commercial borax containing chlorine equivalent to 1.64 per 

 cent, of sodium chloride or common salt. 



No. 2. Practically pure boracic acid. 



No. 3. A commercial preservative containing 3.75 per cent, of com- 

 mon salt, balance boracic acid with a small amount of borax. 



No. 4. A commercial preservative containing 5.41 per cent, of com- 

 mon salt, 9 per cent, saltpetre, balance borax and boracic acid. 



No. 5. A commercial preservative containing 6.5 per cent, of com^ 

 mon salt, balance borax and boracic acid. 



No. 6. A commercial preservative containing 10 per cent carbonate 

 pf soda, balance borax and boracic acid, 



