214 AGRICULTURE OF MAINE. 



Mr. Bradford: What is the science of that, anyway? Why 

 use hot air? 



Answer: Hot air dries the can, and bacteria cannot grow 

 in a dry place. 



Dr. Woods: If we take air and cool it down to above zero 

 degree, the air has practically no water in it, and so we use 

 refrigerating machine with practically no water in it. Water 

 is in the air, and air at certain temperature will contain a 

 large amount of water; as it cools down there will be less and 

 and less water in it. If we could have dry air in Maine there 

 would be probably 90 per cent of the time that cold air would 

 be as dry as the warm air in Boston. A morning like this the 

 air is pretty nearly saturated and the can will not warm the 

 air enough to absorb the water, so the moisture in the can will 

 be condensed. 



Mr. Bradford: You may take ten cubic feet of air, out 

 here where it is moist, and put it into a space and heat it and 

 there is just as much water in it after it goes through the heat 

 as before. That air fills more space than before; there are more 

 spaces or interstices in it; of course it has expanded and yet 

 the water is there. Although the heat in the can won't help it 

 any, I think the warm air would dry out the can more rapidly. 



Dr. GarcElon, of Lewiston Board of Health : We are in- 

 terested in the tuberculin test of milk. Is it possible to so 

 sterilize milk as to render it safe against the germs of tubercu- 

 losis ? 



Answer: American investigators have made many investi- 

 gations; their records show that 150 degrees in 20 minutes were 

 enough to destroy the germs of tuberculosis. Dr. Rosenthal 

 repeated the work of German investigators, also that of the 

 American investigators, to find what is called the thermal death 

 point of disease bacteria in milk. The leaders of sanitary sci- 

 ence in this country have suggested that we use 145 degrees for 

 30 minutes, instead of 150 for 20 minutes, because 150 degrees 

 damages milk somewhat, and 145 seems between the tempera- 

 iture which is not safe and that which damages the milk. I 

 feel that it may be considered safe from tuberculosis. 



