Sterilizing'. To 



The best color for the bottle is none at all, but light 

 hues of color may be admitted if required for dis- 

 tinguishing the different grades of milk. The shape 

 should be conical and running gradually into the 

 neck, avoiding the bulging out at the neck common 

 to medicine bottles. The inside surface of the bottom 

 should be well rounded towards the sides, so that no 

 sharp furrow may exist inside for any sediment to 

 stick in. 



Every bottle with a flaw or bubble should be re- 

 jected, as this will make it burst at sterilizing ; the 

 glass should not be too thick or heavy, and no letter- 

 ing of any kind should be moulded into the face or 

 sides of the bottle, because these raised letters obstruct 

 an equal contraction whilst cooling and thereby cause 

 it readily to burst. The neck of the bottle should 

 be of equal width in all sizes used, so that the same 

 feeding nipple may be applied to all. The stopper 

 must be an automatic sealing one, that is, it must 

 allow the air and gasses which are driven out by the 

 boiling to escape without lifting or moving the stop- 

 per, so that as soon as the pressure from the inside 

 relaxes the stopper shows sufficient adheasiveness to 

 close firmly around the mouth and neck, excluding 

 the outer air; iu fact, it must sit on so firmly as to 

 exclude all possibility of being shaken or pushed off 

 during transportation, but must yet allow of perfectly 

 easy removal by hand. Such a stopper can naturally 

 not have the shape of a plug, but is a hood or caps 

 of the simplest outline, as seen in Fig. 20, yet afford 



