Sterilising. 67 



silver bulb inside in contact with the steam. In 

 some of these apparatus an electric bell has been 

 connected with the thermometer in a manner to close 

 the contact and ring when the quicksilver "has risen 

 to the prescribed degrees of heat ; but as the heating 

 has to be done very . gradually, or a large number of 

 bottles will crack and burst, the operator's hand is re- 

 quired constantly on the steam valve and his eye on 

 the thermometer, so that this electrical arrangement 

 becomes entirely superfluous. 



The inconvenience of losing bottles and their con- 

 tents by bursting was practically overcome by the 

 immersion of the bottles in a water bath, and the 

 success of this simple expedient seemed to prove a 

 lasting one until a singular defect to it appeared, 

 which very speedily caused the abandonment of the 

 water sterilization as far as it was applied in the pro- 

 duction of normal infants' milk. It was found that 

 the bottles used in the water sterilization began, in 

 the course of time, to loose their brilliancy, their sur- 

 face becoming dull and gritty by the action of minute 

 particles of lime which were deposited by the boiling 

 water, and which defied all efforts to remove them by 

 mechanical or by chemical means of cleansing. Al- 

 though this dullness of the glass did no harm to the 

 contents of the bottles, yet it was found impossible 

 now to control the proper cleansing of the bottles, 

 simply because they retain a look of uncleanliness, no 

 matter what sum of exertion has been expended on 

 their cleansing. 



