236 



MILK HYGIENE 



that collects in a given time. Gerber has constructed a 

 special apparatus for this purpose by means of which a 

 fair approximation of the amount of dirt in milk can be 

 made by simply measuring it. 



Generally, the only requirement on this point is that 

 market milk shall not deposit visible sediment upon 

 standing for two hours. [An apparatus for this purpose 

 has also been devised by Otto, which can easily be under- 

 stood by the accompanying figure. The bottle, A, which 

 contains the milk is open at each end. The mouth of the 

 bottle must be closed by a cork held upon a rod, C. A 



FIG. 24. 



O 



Otto's apparatus for estimating dirt in milk. 



fine tube, B, with a still finer point and closed at the thin 

 end, is attached to the mouth of the bottle by a short 

 rubber tube after which the cork on the rod C is with- 

 drawn. The milk is then permitted to stand in this 

 container, held in a rack, for a given tune. At the end 

 of this time, the stopper is replaced in the mouth of 

 the bottle, the small tube is detached and the amount 



