9 



1 shall not enter a discussion on their comparative value, 

 be they composed of Bicarbonate of soda, Borax, Boracic 

 acid, Salicylic acid or the latest by "Effront" Hydrofluoric 

 acid, Fluorites or Formaldehyde. 



No honest man should use either of them in the milk. 



PRESERVING BY COOLING. 



This has, as before said, been used more or less gen- 

 erally less by all milk producers, and, if properly done, is' 

 very effective. 



Most of the bacteria do not develop at a low temperature, 

 which, however, does not kill them. 



It has been demonstrated by "Cnopf" and "Esche- 

 rich " that they multiply in milk at 90 Fah. twenty-three 

 times in 2 hours while at 54 they only multiply four times 

 in the same time and while in four hours at 90 215 times, they 

 only multiply S times at 54. 



To show how enormous the increase is at the favorable 

 temperature (90) it is enough to say that in 6 hours they multi- 

 ply 3800 times. Just think of it! for every one of these little 

 germs, hundreds of which may ride on a speck of dust floating 

 in the air, or left in the seam of the milk can, there will be 3800 

 if the milk is left for six hours at 90 ! If the milk is kept close 

 to the freezing point the increase is hardly perceptible. Ice 

 should thus be the basis for all honest and healthy milk sup- 

 plies and the idea of freezing the milk into solid blocks lies 

 near. 



This has been done in Paris (France) by "G. B. Guerin." 

 The milk was filled in vessels which when frozen by a refrig- 

 erator machine, were insulated for transportation. Frozen 

 milk has been used for years on board ocean steamers. 



As it takes quite a while to freeze milk solid, there is a 

 drawback in its creaming during the process, so that the 

 "block' 7 consists of a very poor layer at the bottom with one of 

 cream on top and a very concentrated not frozen milk in the 

 funnel-shaped indenture in the middle of the block. Thus a 

 thorough mixing after melting is made rather difficult. 



This phenomenon has even been suggested for the con- 

 densing of milk instead of heat, which will be mentioned 

 later on. 



The Casse System (patented about 1894) is based upon the 



