AVERAGE COMPOSITION. 



159 



In the analyses below (Table XXX.) the specific gravity has 

 always been determined by a lactometer ; the fat determinations 

 were made by the Gerber method. The total solids have been 

 calculated by the formula devised by the author. 



TABLE XXX. — Mean Monthly Averages of Milk. 

 (1897-1913.) 



Daily Variations. — It has been found that the percentage of 

 fat varies slightly according to the day of the week, as is shown 

 by the following figures : — 



It is seen that Monday's milk is the lowest in fat ; this is 

 probably due partly to a disturbance in the quality arising from 

 the interval betweon milking on Sunday night and Monday 

 morning not being identical with the usual interval, and partly 

 to the influence of the Sunday holiday on the milkers, reuderins 

 them rather more careless about stripping the cows on Mondays 

 than on other days. 



Morning and Evening Variations. — In England it is the 

 custom to milk cows twice a day ; the quality is not the same at 

 both meals, the evening milk being almost invariably richer in 

 fat than the morning milk. In dairies where it is the custom 

 to leave an interval of twelve hours between the milkings this 

 is far less noticeable than in those where there is an interval of 

 nine to ten hours between the morning and the evening meal, 

 and fourteen to fifteen hours between the evening and the morning 

 meal. 



