182 EXPERIMENT STATION RECORD. 



described. Drops of cream are placed near the edge of a small piece 

 of glass about 12 by 15 in., which is inclined at an angle sufficient to 

 cause the cream to flow down the plate. The glass plate should be of 

 good quality and free from dirt. Several drops of each sample should 

 be used. Cream having the heavier body moves more slowly down the 

 glass, and the length of the several cream paths is taken as a measure 

 of the relative consistency. 



The authors found that the viscosity of pasteurized cream could be 

 restored by adding freshly slacked lime in solution. As lime is com 

 paratively insoluble in water, a solution of sugar and water was used 

 as a solvent. The lime solution is prepared as follows: 



"Two and one-half parts by weight of a good quality of cane sugar (granulated) 

 are dissolved in 1 part of water; and 1 part of quick lime gradually slaked in 3 parts 

 of water. This milk of lime should be poured through a wire strainer to remove 

 coarse unslaked particles and then added to the sugar solution. The mixture should 

 be agitated at frequent intervals, aud after 2 or 3 hours allowed to settle until the 

 clear supernatant fluid can be siphoned off. 



''Where large quantities are made, we have found it convenient to mix the ingre- 

 dients in a revolving barrel churn. The (dear liquid (viscogen) should be kept in 

 well-stoppered bottles which are filled full for the reason that it absorbs carbonic 

 acid from the air, thus reducing its strength, and also because, where air has access to 

 the solution, it darkens in color after a time. This latter chemical change, however, 

 does not seem to impair its usefulness. 



•The quantity of lime recommended in the above formula is considerably more 

 than will be dissolved by the sugar solution. This excess is added because of the 

 impurities contained in our Wisconsin lime, which is of dolomitic origiu, and hence 

 contains nearly as much magnesia as lime. As these impurities are practically 

 insoluble in the sugar solution they have no effect in the prepared viscogen. 



"After siphoning off the clear fluid, the residue still contains some of the sugar 

 solution, that remains turbid for a long time. This sugar can be recovered by adding 

 considerable water to the residue and allowing it to settle again, when the clear liquid 

 can be poured off and used in the place of an equal quantity of water in the prepara- 

 tion of the next lot." 



This solution of lime in sugar is called "viscogen," and the treated 

 products visco cream, visco-milk, etc. Viscogen is strongly alkaline 

 and should be used with care. Under no circumstances should a suffi- 

 cient amount be added to cream to render it alkaline. Enough should 

 be added to almost neutralize the acid of the cream. The authors 

 recommend, as a simple method of determining the amount of viscogen 

 required, to add it to a measured sample of the cream, testing with 

 phenolphthalein or other indicator which shows when the neutral 

 point is reached, and from this to calculate the amount of viscogen to 

 be added to the total amount of cream. 



"Certainly no objection can be raised from a sanitary standpoint to the amount 

 of sugar added. Lime is a normal constituent of milk, and the amount added to the 

 prepared cream should never exceed 4 parts in 10,000, which "is really less than the 

 usual variation in lime content between milks from different sources. Hence, its 

 physiological effect is trivial. Furthermore, lime in solution is commonly prescribed 

 by physicians to be added to the milk designed for infants and invalids, which of 

 course would not be done if it were injurious. 



