180 STATE BOARD OF AGRICULTURE. 



licate. The plates after 7 days' incubation showed from 1 to 5 colonies per 

 plate. These were regarded as probably the result of contamination in 

 plating. Direct microscopic examination of the milk by Breed's technique 

 revealed no bacteria. Considerable cellular debris — nuclei and pieces of 

 nuclei of body cells — ^were found. 



Unstained milk placed under coverslips and examined under the micro- 

 scope showed very tiny fat globules not clumped as in ordinary milk. This, 

 together with the fact that it was extremely easy to restore a perfect emul- 

 sion upon shaking, led to the conclusion that this was homogenized milk. 

 On tasting the milk, the custard-like taste of repeatedly pasteurized milk was 

 noticeable. Like all overheated milk, this product tasted slightly, though 

 not unpleasantly, astringent. The remainder of this bottle of milk was 

 transferred aseptically to a series of sterile test tubes and held at room tem- 

 perature to see if it would sour. After 4 days it was still sweet. 



Another bottle was opened and tested for acidity. Five cc. required 2 cc. 

 ^ NaOH. This is equivalent to 0.18% acid calculated as lactic acid. This 

 milk was tested b}^ the Dairy Department for l)utterfat by the Babcock 

 method and found to contain 3.2% fat. 



Two other bottles were held for 3 months, one in the ice box and the other 

 in the 3,7°C. incubator. At the end of this period, the milk held in the ice 

 box was still fluid and sweet while the milk held in the incul^ator was curdled 

 and had wheyed off. This tasted only slightly sour and unpleasant. Acidity 

 tests made on both milks give the follo^^^ng results : 



37° C milk, 5 cc. = 6.68 cc. ^ Na OH. 

 Ice Box milk, 5 cc. = 2.25 cc. ^ Na OH. 



When ]:)lated in triplicate on lactose agar, the bacterial counts after six 

 days incubation at room temperature were as follows : 



37° C milk gave 52,000 colonies per cc. 

 Ice box milk gave 40 colonies per cc. 



A number of spore bearing rods were isolated from each milk but as it 

 was impossible to reproduce the type of curd in the original, by ordinary cul- 

 tures, anaerobes were suspected. Accordingly, several tubes of sterile litmus 

 milk were inoculated with loopfuis of ice box Ever Fresh Milk and covered 

 with an 18 mm layer of sterile paraffin. After incubation at room temper- 

 ature for a week, the paraffin plug in one of the tubes was raised about 12 

 nun. and some of*the milk was above the plug. That above the plug was 

 acid in reaction, while that below showed the Htmus reduced to the leuco 

 compound. On plating,and fishing the colonies which had grown anaerobically , 

 four cultures were obtained and grown by anaerobic methods on lactose agar. 

 These produced gas from the lactose in the agar so that it was blown full of 

 holes and separated into sections. The colonies on the plates were small, the 

 surface colonies being round and the sub-surface being lens-shaped. All were 

 sporebearers with large round spores terminally placed in a slender rod. The 

 spores were larger in diameter than the rods giving the appearance of a nail 

 with a round head. These grew well on agar slants in Giltner H-tubes con- 

 taining NaOH and pyrogallic acid in the second tube of the H. Two of them 

 failed to grow when transferred to an ordinary aerobic slant while two grew 

 well on the slant. 



