CJEEBER METHOD. 



235- 



and if the temperature be 11° and the specific gravity r827, the 

 corrected specific gravity will be 1-827 — 4 X 0-001 = 1-823. 



Pure amyl alcohol — specific gravity, 0-8165 to 0-818 at 15° 

 (59'- F.) ; boiling point, 124° to 130° C— should give a clear 

 solution with an equal volume of strong hydrochloric acid. 



Amyl alcohol sometimes contains petroleum, due to the use 

 of empty petroleum barrels as packages. A blank test with the 

 Gerber method fails to reveal the presence of petroleum if the 

 quantity is below 2 per cent., a quantity which gives an error of 

 about 0-2 per cent, in the fat estimation. 



It may be detected by running 10 c.c. of sulphuric acid, 10 c.c. 

 of water, and 2 c.c. of amyl alcohol into a Gerber butyrometer, 

 mixing and centrifuging ; no layer should appear if the amyl 

 alcohol be free from petroleum. If present an approximate 

 estimation of the quantity may be made ; the following results 

 were obtained by the author and Goodson : — 



It is advisable to have a bottle of ammonia handy in case acid 

 is spilt on the clothes ; should this happen an application of a 

 few drops of ammonia at once will prevent damage. 



If strong acid is spilt on the skin, wash copiously with cold 

 water without delay and the white swellings formed will soon 

 disappear. 



Mode of Operation. 



Milk, Skim Milk, W/h'i/ and Biitlennilk. — Place a sufficient 

 number of acido-butyrometers in the stand, open end upwards, 

 aud run 10 c.c. of acid into each. Well mix the samples to 

 lie tested and measure with the milk pipette, 11 c.c. of each 

 into the bottles ; add 1 c.c. of amyl alcohol. 



Mi-asuring liquids bv means of pipettes is done as follows : — 

 Hold the pipette near its upper end between the thumb and 

 the middle finger of the right hand, insert the lower tapering 



