714 EXPERIMENT STATION RECORD- 



of tlu- I'voniii^' milk. On only one occasion were the solids-not-fat below the legal 

 shuulard of 8.5 per cent. The resulta for the second herd showed less than 3 per 

 cent of fat on 5 out of 124 occasions in the morning and 11 out of 123 in the evening; 

 and solids-not-fat less than 8.5 on 1(5 out of 122 occasions in the morning and 21 out 

 of 124 in the evening. 



Summarizing the results of the present study with those reported in a previous 

 paper (E. S. R., 14, p. 695), it was found that 96 tests out of 984, or about 10 per 

 cent, were below the standard. "These figures suggest that there is some truth in 

 the opinion that milk in the north of England is not as rich as that in the south, and 

 can not be judged by the same standard." On the basis of the testsof individual cows 

 the author discusses tlu; probability of the mixed milk being below the standard. 



Aerated preserved milk [Brliklt- Med. Jour., 1904, No. 2245, pp. 84-86) .—This is 

 an editorial account of the preservation of milk by aeration and pasteurization aa 

 carried out l)y a dairy company in England, the process consisting in (1) heating the 

 milk to 150° F. and passing it through a machine in which the fat globules are broken 

 up into small particles; (2) cooling to 40°, and aerating with a mixture of oxygen and 

 carbon dioxid (3:1) under pressure of 50 lbs. ; and (3) bottling in sterilized bottles 

 and corking tightly, heating to 150° for 30 minutes, cooling, and again heating as 

 before. 



Milk bottled November 2, 1903, was sweet when tested December 8; an exception 

 being made of 2 half-pint bottles which kept only until November 24. After opening 

 the bottles the milk remained sweet at laboratory temperatures for from 4 to 8 days, 

 which is considered the most remarkable fact in connection with the milk. The 

 milk tasted perfectly sweet, although not absolutely the same as fresh milk. There 

 was, however, no taste of boiled milk. The cream showed no tendency to rise, and 

 could not be separated by centrifugal force. The main physical difference between 

 this milk and fresh milk was in the extremely fine subdivision of the fat globules in 

 the former case. No differences were observed as regards the quantity or quality of 

 the different constituents. Artificial digestion experiments showed no difference in 

 the digestibility of the treated milk and fresh milk. All 3 processes — the disintegra- 

 tion of the fat globules, aeration, and heating to 150° — were found essential to the 

 success of the method. 



The process of aeration and subsequent heating, as shown by bacteriological inves- 

 tigations, did not completely destroy all spore-bearing bacteria. Diphtheria bacilli 

 added to the milk were not destroyed by aeration alone, but were apparently by 

 aeration and subsequent heating. Caseous material from a tuberculous guinea pig 

 was added to milk, one bottle being kept as a control and one subjected to aeration 

 and heating. A guinea pig inoculated with the sediment from the control bottle 

 developed typical tuberculosis in 18 days, while 2 guinea pigs inoculated .with the 

 treated sample showed no signs of the disease upon autopsy at the end of 28 days. 



Homog'enized milk, P. Buttenberg {Ztschr. Untersudi. Nalir. ?f. Genussmtl., 6 

 {J903) , No. '20, pp. 964-968) . — Attention is called to the effect of heat and mechanical 

 action in delaying the spontaneous separation of cream, and a description is given 

 of the method of Gaulin for rendering milk homogeneous in which these 2 factors, 

 as well as that of pressure, are utilized. In this method nulk heated to 85° C. is 

 forced under pressure of 250 atmospheres through tubes of 1 mm. diameter and then 

 between closely api)lie(l plates of agate and metal, by which process the fat globules 

 are very finely divided. 



While the fat globules in ordinary milk may vary in size from 0.0016 to 0.0100 

 ram., those in milk treated by this method measure usually about 0.0008, and seldom 

 exceed 0.0028 mm. No separation of the fat was observed in a sample of this milk 

 6 months old, although it had been kept at 37° for 1 week. The apparatus in most 

 common use requires 7 horsepower and permits the treatment of about 1,000 liters of 



