14 



They should {hen be well rinsed out with hot water. This will 

 often be sufficient to clean them ; but if any of them show any 

 signs of greasiness they should be soaked in a strong solution 

 of soda and afterwards rinsed out with hot water. A set of 

 rinsing jets, consisting of narrow tubes sufficiently long to 

 reach to the bulb of the bottles, and which can be screwed on to 

 the hot water supply pipe will materially aid in this part of the 

 work. Test bottles cannot be satisfactorily cleaned if they are 

 allowed to cool before being emptied. The difficulty of obtain- 

 ing a clear reading is often due to dirty bottles. Moreover, un- 

 seen fat left from a previous test in a dirty bottle is very 

 frequently a source of considerable error. 



The rubber stoppers need special attention. Immediately after 

 the test these stoppers should be washed in hot water until they 

 are free from acid, and then carefully dried. If left unwashed 

 they become hard and useless. The dirty layer which is often 

 seen under the column of fat is frequently due to granular 

 matter from dirty stoppers. 



A. T. A Go. (Ltd.) 

 (G.60) 1.1903. 



