12 GENERAL CONDITIONS AFFECTING BACTERIA IN MILK 



gland becomes enlarged by an increase in the size of existing, 

 and possibly, by the formation of new, alveoli. Within the alveolar 

 cell granules of a proteid and fatty nature become collected, and 

 the alveoli become filled with a clear fluid which contains a few 

 fatty globules and composite corpuscles. These latter cells are 

 amoeboid and probably derived from migrated leucocytes. Their 

 occurrence produces a thickened slimy secretion known as colostrum, 

 which is yellower and more alkaline than fully-formed milk, and 

 sometimes contains a certain amount of blood. 



Schafer ^ gives the exact composition of colostrum by various 

 authorities as follows : — 



Colostrum therefore differs from milk in that it contains less 

 sugar, a fat which is very poor in volatile acids, and a high per- 

 centage of nitrogenous compounds. Milk containing colostrum is 

 not used for dairy purposes ; from three to five days should elapse 

 after parturition before the milk is employed for human con- 

 sumption. It may be useful for reference to append the following 

 table, for the data of which Houdet is responsible : — 



1 Text-book of Physiology. E, A. Schafer, F.R.S., p. 129. 



