THE ANALYSIS Of MILK 663 



The Ro)al Commission on vSewage Disposal recommended ihat an 

 effluent "should not contain more than 3 parts per 100,000 of sus- 

 pended matter; after being filtered it should not absorb more than 

 o'5 by weight of O2 per 100,000 in twenty-four hours. 

 I'o b\' weight of O. per 100,000 in forty-eight hours. 

 r5 by weight of O2 per 100,000 in five days." 

 Chlorine should not exceed 10 parts per 100,000. 

 O2 absorbed in four hours at 60° F. (or two hours at 80° F.) and 

 the saline ammonia should not exceed 1*5 per 100,000. 

 The albuminoid ammonia not more than o'i5 part. 

 Incubation of final effluent when at 37° C, and for five days should 

 be odourless. 



Generallv high nitrates are a good feature. 



THE ANALYSIS OF MILK. 

 The Average Composition of Cow's Milk is : — 



Total Solids I2"6 per cent. 



Water ... 87*4 per cent. 

 Fat ... 373 ., 



Lactose ... 4*50 ,, \ 



Proteins ... 3"62 ,, - Solids not fat 8"87 per cent. 



, Mineral matters 075 ,, ) 



The specific gravity is about 1032 at 15° C. 



(1) To Estimate the Total Solids. 



Weigh a small porcelain dish. 



Put therein 10 c.c. of milk and reweigh. 



Evaporate to dryness on a water bath for one hour. 



Dry in an oven for one hour. 



Cool in a desiccator and weigh. 



Dish+ 10 c.c. of milk = 36*320 grm. Dish + total solids = 27722 grm. 



Dish = 26"4oo „ Dish = 26*400 „ 



Milk weighs ... 9*920 grm. Total solids ... 1*322 grm. 



Hence 100 grm. of milk will contain : — 



= 13*32 per cent, of total solids 



1*322 X 100 



9*920 



(2) To Estimate the Ash or Mineral Matter. 



Heat the residue from the above to a white ash on a porcelain 



triangle. 



Stir with a glass rod meanwhile. 



Cool in the desiccator and weigh. Suppose ash is o"076. 



100 grm. of milk contains about o'76 per cent. 



0*076 X 100 



9*920 (= weight of milk) = 76 per cent. 



42 



