VARIATION OF TOTAL SOLIDS 



Variation of Total Solids. As applied to milk, " Total 

 Solids," is a term that includes fat, casein, albumen, sugar, 

 and ash; in other words, all the milk constituents except the 

 water. " Solids Not Fat " is a term often used, and includes 

 the casein, albumen, sugar, and ash, or all the milk constituents 

 except water and fat. " Serum " is a term used to designate all 

 the milk constituents except the fat. The fat is the most val- 

 uable constituent of the total solids. The variation in the total 

 solids of milk during the summer months is shown in the table 

 quoted below from Dr. Van Slyke of Geneva, New York: 



Dr. Van Slyke also studied the effect of the lactation period 

 upon the total solids in milk. A herd of fifty cows, calving in 



