Thu Mojonniur Test 289 



flask into flask holder. Shake thoroughly and see that no milk ad- 

 heres to any part of flask undissolved. In case particles of milk 

 stick to side of flask, shake thoroughly until these are washed away. 

 It is of the utmost importance to shake thoroughly at this point. 



(4) Add 25 c.c. ethyl ether, insert corks and shake vigorously, 

 lengthwise of flask, with liquid in large bulb of flask, and small bulb 

 extended upward- Stop shaking at end of five seconds until all 

 liquid has run into large bulb and repeat vigorous shaking for four 

 five-second periods. 



(5) Add 25 c.c. petroleum ether and shake in same way. 



(6) Place extraction flasks into centrifuge and whirl for 

 thirty turns at speed of about 600 R. P. M. Double time for sweet- 

 ened condensed milk. 



(7) Place four 3j^-inch dishes in line on shelf adjoining hot 

 plate, keeping them in order in which their weights were posted 

 upon record sheet. Aim to have numbers on flasks correspond with 

 number of dishes. 



(8) Pour ether extraction to dividing line into proper 

 dishes and slide dishes over onto hot plate, which should be held 

 at a temperature of 135 degrees C, as indicated by thermometer in- 

 serted in nickel plated mercury well. 



(9) Repeat the extraction, adding first alcohol enough to 

 bring line close up to top of small neck of flask, then 25 c.c. ethyl 

 ether, and then 25 cc. petroleum ether, and shake vigorously after 

 the addition of each of above three reagents for four 5-second 

 periods. 



(10) Whirl in ceritrifuge for thirty turns. 



(11) Move aluminum dishes back upon shelf adjoining hot 

 plate and pour the second extraction into proper dishes. Never 

 pour extraction into hot dish. Remove dish from hot plate as soon 

 as ether is all evaporated. 



(12) when all of ether has evaporated place dishes into 

 vacuum oven, which should have a temperature of 135 degrees cen- 

 trigrade. Keep them there for five minutes after the vacuum gauge 

 shows at least twenty-two inches of vacuum. 



(13) Place dishes into cooler for seven minutes, with pump 

 outfit running. See that water is running through cooling plates. 



