9 



his belief in this system and though I do not share this belief, it- 

 may be of interest to put it on record here. Figs. 1 and 2 represent 

 the proposed can, A is the body of the can preferably enamelled, c 

 is the piston screw which is turned by the handle D. B is the piston 

 head with valve G opening up 'and F opening downwards. H is the 

 opening in the cover and J a slide which slides in a groove on the 

 lower side of the cover. 



Suppose the pistonhead B is at the top ab, the can is full of 

 air. By screwing the pistonhead down to cd the air is expelled 

 through the valve G. 



The milk is now poured in by the opening H so as to fill the 

 whole can and the opening H as well. This drives all (or nearly all) 

 the air out and the slide J is closed. 



Pistonhead is then screwed up to ab, letting the milk through 

 by F into the space c d e f where it is free from air. 



When the milk is needed, a few turns on piston will press some 

 through G and it is poured out by H. The apparatus is cleaned by 

 unscrewing the cover at v and the inside of the can as well as the 

 pistonhead may be made of glass! 



Granted that this process will do all that it is claimed, granted 

 it will prevent the cream from rising, granted that the anaerobic 

 microbes cannot develop without their aerobic cousins have prepared 

 the way for them and granted that the latter cannot live without air. 

 Granted all this, my readers will agree with me that the cost of such 

 cans would preclude their use. 



PRESERVING BY ELECTRICITY. 



This, like butter and cheesemaking by electricity, has been 

 talked about, but while experiments seem to have proved that elec- 

 tricity may to a certain extent paralyse microbes, nothing practical 

 has been evolved as yet. 



PRESERVING BY HEAT. 



It has been shown how the bacteria germs develop best at about 

 blood heat and how their development is reduced all the more, the 

 colder. they are kept, but excessive heat has a similar and even bet- 

 ter effect. This has been known for ages and the preservation 'of 

 milk and cream by boiling is a common precaution among house- 

 keepers. 



Yet, unless the milk is cooled down and kept cool, the effect is 

 only to keep it sweet for 12 to 24 hours longer and the boiled taste, 



