178 PRACTICAL BOTANY 



disease-bearing materials of all kinds ; l to have large quan- 

 tities of fresh air ; to have all the sunshine possible, for sun- 

 shine is destructive of many disease germs. 2 



It is of great importance also that a high standard of vigor 

 be maintained as a means of preventing bacterial disease. 

 Many people have had disease-producing bacteria introduced 

 into their bodies without any serious consequences, indeed 

 without even being conscious of danger. Their bodies were 

 in such vigorous condition that the initial growth of bacteria 

 was prevented. An instructive experiment relative to this 

 point was performed by Pasteur. Ordinary domesticated fowls 

 are not readily susceptible to anthrax. Pasteur found, how- 

 ever, that if he kept the fowls at lower temperatures than was 

 normal for them, they were very susceptible to anthrax and 

 that under such circumstances it proved deadly to them. This 

 is a common principle in hygiene. When through excessive 

 fatigue, loss of proper sleep or nourishment, or for any other 

 reason, bodily vigor is greatly reduced, susceptibility to disease 

 is increased. 



Modern bacteriology has offered the human race the means 

 of escape from many diseases. Ignorance, lack of care, and 

 financial greed are often the only excuses that can be offered 

 when certain diseases occur. If only those who are responsible 

 for them might be attacked by these preventable diseases, the 

 matter would not be so serious, for in that case disease and 

 the resulting deaths would tend to eliminate those who do 

 not act upon the knowledge of sanitation which we now 



1 In Bacteria, Yeasts, and Molds in the Home, by H. W. Conn (Ginn and 

 Company), there is an excellent popular discussion of the nature of bacteria 

 and the effects of their growth. 



2 In Germany it is unlawful for filtered water to contain more than 100 

 bacteria per cubic centimeter, and it should always contain less. Boston 

 has a legal standard which requires that market milk shall not contain more 

 than 500,000 bacteria per cubic centimeter; and Rochester, New York, and 

 Milwaukee, Wisconsin, have legal standards of 250,000 per cubic centimeter. 

 Some kinds of certified milk may contain less than 10,000 bacteria per cubic 

 centimeter. On the other hand, in impure milk the number may run from 

 several hundreds of thousands to several millions. 



