586 



The Cotmtry Gentlemmi s Magazine 



after creaming, of 1033.5 ; but the milk of 

 the same cow varies from time to time, be- 

 coming much richer after calving. The 

 average richness of the unadulterated milk 

 from a number of cows ought not to be less 

 than the standard above given. If a milk 

 yields less than 10 per cent, but not less 

 than 5 per cent, of cream, or if it has 

 a specific gravity when skimmed of not 

 less than 10.30, it is either the produce 

 of poor cattle, or it has been watered, 

 or robbed of cream. In many parts of Man- 

 chester and Salford, a few cows are kept in 

 small stuppons in the town by people who 

 retail the milk. In some cases the cows are 

 kept entirely on grains, meal, &c., never 

 entering a grass field. Such cattle occa- 

 sionally give very poor milk. The milk of 

 one cow thus kept and fed, gave barely 5 per 

 cent, of cream. Of about 100 specimens of 

 milk obtained directly from different cows 

 fed and kept in various ways, this was the 

 worst. A milk v.-hich gives less than 5 per 

 cent, of cream, or has a specific gravity when 

 skimmed below 10.30, has certainly been 

 robbed of its cream or watered. The test 

 enables a judgment to be formed as to the 

 means by which a milk has been rendered 

 poor. If it gives 5 to 7 per cent, of cream, 

 and when skimmed has a specific gravity of 

 not less than 10.30 it possibly comes from 

 poor cattle, though it may be a rich milk 

 Tobbed of its cream and slightly watered. 

 Milk giving 6 to 7 per cent, of cream, and 

 liaving a specific gravity of 10.20 to 10.25, 

 has probably been rendered poor by adding 

 water to good milk. If the same gave only 

 2 to 3 per cent, of cream it would probably 

 have been robbed of cream as well as 

 watered. Milk yielding 5 to 7 per cent, of 

 cream, and having, when skimmed, a specific 

 gravity of 10.32 to 10.33, ^^^.s probably been 

 robbed of its cream and watered. 



Not unfrequentiy skimmed milk is added 

 to new milk, and the mixture sold as new 

 milk. This is equivalent in effect to robbing 

 the cream, and is thus indicated by the cream 

 measurer. In using the test, as above given, 

 certain precautions must be taken, or other- 

 wise but little reliance can be placed on the 



results obtained. The quantity of cream 

 rising to the surface of milk in narrow vessels 

 varies much according to the temperature, 

 and somewhat, also, according to the amount 

 of shaking to which it has been exposed. If 

 kept continually above 60 deg. to 65 deg. 

 unadulterated milk may not give 10 per cent, 

 of cream. The following experiment shews 

 how temperature affects the yield of cream : — 

 Four cream measures were filled with the 

 same milk, which was known to be unadul- 

 terated. One was kept at about 40 deg., one 

 at about 60 deg., and a third between 65 deg. 

 and 70 deg., and a fourth a little above 80 deg. 

 The temperatures were maintained about 

 twelve hours. At the end of that time No. 



1 gave 11^3 per cent, of cream ; No. 2 gave 

 10 per cent, of cream ; No. 3 gave 7 per cent, 

 of cream; and No. 4 gave 4 per cent, of cream. 

 In ascertaining the amount of cream present in 

 a milk, therefore, care must be taken that the 

 cream measurer be kept in a cool place. In hot 

 weather it is best to let the milk stand during 

 the night for this. In the height of summer, 

 if the night temperature does not fall below 

 65 to 70, a good milk may not shew more 

 than 7 per cent; but if the thermometer sink 

 for a portion of the time to 60 deg., to 63 

 deg., 10 per cent, of cream will be obtained 

 from milk of average goodness. Should the 

 cream measurer and contents be left all night 

 in a hot kitchen, it might happen that the 

 ordinary amount of cream would not rise to 

 the surface even of good milk. Milk carried 

 through the streets or otherwise much shaken 

 gives somewhat less cream than the same 

 milk not so treated. In specimens of milk 

 of known purity, taken before the round and 

 after it, there was a difference of from i to 



2 per cent, in the cream yielded. This may 

 in part arise, however, from the mode of 

 distribution. The cream in the cans is con- 

 tinually rising to the surface, and, as the milk 

 is usually ladled, hence the first part of the 

 milk distributed will contain somewhat more 

 and the latter somewhat less cream than is 

 natural. This is the more likely to be the 

 case in milk that has been adulterated with 

 water, since cream rises quicker in watered 

 than in pure milk. No means can be de. 



