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CHAPTER IV. 



THE rilEMICAL CONTROL OF THE BAIRY. 



CciNTENTS. — Duties of the Dairy Chemist — The Testing of Milk — Deter- 

 mination of Spocilic Gravity — Estimation of Total Solids — of Fat and 

 Butter — The Control of Milk during Delivery — The Solution of 

 Analytical Problems — Cause of Low and High Specific Gravity — of 

 Sweet Taste — of " Poor " Milk — of unusual Taste and Smell — of Milk 

 being Curdled — of Milk being Thick — Nature of Sediment — Skim 

 Milk— Cream. 



Duties of the Dairy Cliemist. — The duties of the daiiy chemist 

 consist in the following : — 



(1) To see that the milk at or from the farms is of good quality, 

 containing a full percentage of cream, is not tampered with by 

 the emiiloijes, and is in good condition. 



(2) if milk is sold by retail, to see that the milk sent out is of 

 good quality, and, by analysing samples taken without notice 

 from the cmploi/i'; in charge of the milk, to ascertain that it is 

 delivered in the same condition as it left the dairy. 



(3) To see that cream separators, churns, etc., are worked in 

 the most efficient manner, by examining the various products, 

 and to obtain such figures representing their composition as will 

 allow of accounts being kept of the manufacturing processes. 



(4) To ensure that all products derived from milk are of good 

 quality. 



(5) To investigate specially products deemed unsatisfactory, 

 and to elucidate the cause for dissatisfaction. 



(G) To make chemical examinations of water supplies, disin- 

 fectants, etc., so as to ensure that sanitation is carried out by 

 reliable means. 



(7) To advise on chemical questions that may arise — e.g., the 

 suitability of metals for the construction of dairy apparatus, the 

 examination of waters or boiler compositions for steam produc- 

 tion, the analysis of feeding stuffs and fertilisers, etc. 



A description of the duties of a dairy chemist must uecesisarily 

 be somewhat hypothetical, as the conditions in different dairies 

 differ exceedingly from each other. In large dairies the chemist 

 is an official wholly responsible for his own department, and 

 under the control of no one except the proprietor. It is not 



