BACTERIA 



197 



3. Plants without clilorophyll find suitable nourishment not 

 only in decaying matter, but also in living organisms. It is no 

 wonder that Ave should, 



therefore, find numerous 

 parasites among the Bac- 

 teria. They penetrate the 

 bodies of animals and 

 men, multiply there at a 

 rapid rate, and produce 

 a number of deadly dis- 

 eases. Of these diseases 

 we shall mention here 

 only these few : — Con- 

 sumption, of w^hich one- 

 seventh of all men die; 

 typhoid fever, diphtheria, 

 pneumonia, and influenza, 

 Avhich also every year 

 destroy a great number of 

 men in the prime of their 

 life, and cholera and 

 plague, which are the 

 most terrible scourges to 

 which a country can be 

 subjected. 





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Fig-. 180. — Bacteria of tuberculosis, typhus, 



diphtheria, pneumonia, influenza, cholera, 



plague, etc. 



It is right that we should learn to know hotv to meet these poiver- 

 ful e7iemies. One of the means to keep these ''omnipresent" microbes 

 aw^ay from us is the greatest cleanliness. This holds good of the 

 vessels in which we prepare and preserve our food, of our houses 

 and their surroundings, of our garments, and, above all, of our own 

 bodies. As show^n in the above experiment, Bacteria perish at the 

 temperature of boiling ivater. This supplies us with a means of 

 keeping good, for some time at least, a number of food substances, 

 such as meat, fruit, vegetables, milk, etc., w^hich would otherwise soon 

 be spoiled. From immemorial times, men have also been using salt 

 to preserve meat and to pickle fruits, sugar to candy them, and smoke 

 to preserve meat. Besides, there are some drugs, called antiseptics^ 

 which also destroy Bacteria or prevent their action. 



