202 THE CREAMERY PATRON*S HANDBOOK. 



number of globules per cubic centimeter may be two or three times as 

 great as at first, but the size correspondingly smaller and the per cent, 

 of fat approximately the same. 



P. Collier records 1 the results of a large number of determinations 

 of the size of the globules in the milk of different breeds. The size of the 

 globules diminishes as the period of lactation advances, that is the relative 

 number of large globules diminishes and the smaller globules increase. 

 He found 2 that the relative number was 100 in the first quarter, 137 in 

 the second quarter, 149 in the third quarter, and 187 in the fourth quarter 

 of the period of lactation. That is, a given quantity of milk contained 

 89 per cent, more fat globules in the last quarter than in the first. 



O. Schnellenberger 3 found essentially the same thing, and estimated 

 that a liter of milk contained 2,480 millions of globules at the beginning 

 and 4,449 millions of globules at the end of the period of lactation. 



F. W. Woll agrees with the previously cited writers and further adds 

 that age has no apparent effect, and that the morning milk contains more 

 large globules than the evening milk. 



The milk from certain breeds, as Jerseys and Guernseys, is charac- 

 terized by large globules, while that of other breeds, as Ayrshires and Hoi- 

 steins, usually contain small globules. There is, however, a wide indi- 

 vidual difference in all breeds, Jerseys sometimes producing small globules 

 and Holsteins large ones. In normal milk the globules are uniformly dis- 

 tributed throughout the whole mass, but to a greater or less extent col- 

 lected in groups. For a long time it was thought that each cell was sur- 

 rounded by its own membrane, the membrane of Acherson. This mem- 

 brane was supposed to be derived from the cell of protoplasm. According 

 to Babcock no such membrane exists, and he is supported in this view by 

 nearly all recent investigators. It is now considered that milk is a nat- 

 ural emulsion, and that what appears to be a membrane is not different 

 from what is seen in other emulsions, having the fat similarly divided. 



The fat of milk is very complex, being a mixture of six or eight distinct 

 fats, some being volatile and others not. The following in Table 4 is 

 the composition submitted by Wiley. 4 



TABLE 4. 



COMPOSITION OF BUTTER. . 

 INSOLUBLE FATS. 



Olein 42 . 21 Oleic acid 40 . 40 



Stearin and palmatin 50 . 00 Stearic and palmic acid 47 . 50 



92.21 87.90 



1 New York Experiment Station, Report 1891. 



2 Experiment Station Record, Volume V., p. 95. 



3 Experiment Station Record, Volume V. p. 95. 



4 Principles and practice of Agricultural Analysis. H. W. Wiley, 1897. 



