HOUSEHOLD BACTERIOLOGY 63 



to prevent the raising of dust and to avoid the use of cloths or utensils 

 not thoroughly cleansed. Persons will give themselves much concern 

 in sterilizing fruit and jars, and then wipe out the clean jar with a 

 dishcloth or let their fingers come in contact with the inside of the jar. 

 Everything that comes in contact with fruit or receptacle should not 

 only be clean but should also be sterile. 



Cans must be sealed while still hot, so as to sterilize any air present. 

 New rubber rings should be used each year, as they need to be soft and 

 elastic, and they should be heated in water before being used. Sterili- 

 zation can be accomplished much more thoroughly in factories than in 

 private houses, because the former have equipment to produce sterilization 

 under pressure. Never is the housekeeper more conscious of the necessity 

 of exact laboratory principles than when she is canning her fruit; it is a 

 piece of work of which to be proud, when she does it with the exact- 

 ness of scientific principles. 



DISEASE GERMS 



A growing knowledge of bacteria has done much toward preserving or 

 prolonging life. Some persons still state that they are happier if they do 

 not know too much about germs. They affirm that before germs were 

 known people were just as healthy as, and much happier in their ignorance 

 than, at the present time. They confound knowledge with fear. Knowledge 

 teaches prevention; fear preys on the mind. A lack of knowledge of how 

 to avoid infection is inexcusable among the intelligent. An infected 

 person should be isolated for the welfare of his fellow-beings, even though 

 he is suffering merely from a cold. Every one now understands that a 

 cold is contagious. With isolation to prevent others from becoming 

 infected, and disinfection to kill already existent germs, sickness and the 

 death rate would be soon and greatly reduced. A student who was 

 interested in his work had mumps. He was asked by his instructor to 

 remain away from class until he was well. On his refusing to do so, the 

 dean Q the college told him that he must leave the college until he was 

 pronounced safe. The student said that he could not understand why 

 he should not remain in the college because it was his mumps. The 

 truth is that he could not keep his mumps to himself. 



Some micro-organisms are parasites that produce disease. They feed 

 on living plants and animals. Other micro-organisms live on both living 

 and dead material. They are only partly parasitic and are capable of 

 producing disease. Those microbes that cause disease are said to be 

 " pathogenic." It is now known that microbes are the cause of many of 

 the contagious or infectious diseases, such as tuberculosis, diphtheria, and 

 typhoid fever. The better the conditions for the propagation of these 



