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saving many thousands of lives. Health can only be attained by 

 thorough cleanliness, both personal and chemical, and by adopting 

 all proper sanitary precautions in our houses and our towns. All 

 poisonous germs thrive in darkness and in dirt, but are speedily 

 put to flight by sunlight, pure air, and pure water. Indeed the 

 virulence of some known germs is practically destroyed simply by 

 exposure to the light, thus affording a fresh proof of the supreme 

 importance of allowing sunlight to enter and purify our houses. 



It was formerly, but erroneously, supposed that microbes were 

 minute bodies of a very low form of animal life. This idea arose 

 from the fact that they are capable of spontaneous movement. 

 They are, however, of vegetable nature of the fungus tribe, closely 

 allied to those minute vegetable organisms known as amoebfe (from 

 their inherent power of changing their shape), and to the infusoria 

 met with in stagnant water. Many years ago both amoebae and 

 infusoria were described as animalcule, but now that microscopic 

 observations are made with much greater accuracy, the vegetable 

 nature of these minute organisms has been clearly proved. Most 

 germs are capable of motion, and some appear able to avoid or to 

 free themselves from contact with other bodies. Their usual 

 method of propulsion is by means of a minute point at either end 

 of the body, called a flagellum. All germs are commonly termed 

 bacteria, although the name baterium (a little staff) is really only 

 applicable to the oval species, of which alone there are over fifty 

 varieties. The long, thin, rod-like germs are called bacilli 

 (bacillus, a little rod), and include forty different kinds. The 

 round germs or dots are known as micro-cocci (micro-coccies, a 

 small kernel), and number over eighty varieties. In addition to 

 the three principal species of germs already mentioned, there are 

 the spirilli, curled hair, or spiral-shaped germs, the streptococci 

 (twisted kernels), and the staphylococci (grape-like kernels). 



Many microbes have already been identified as causing specific 

 forms of disease, and although the study of bacteriology is at 

 present only in its infancy, it is believed by many scientists that 

 every infectious disease is due to some special germ. Already the 

 specific microbes o! pneumonia, phthisis, diphtheria, cholera, 

 leprosy, and ringworm have been identified, separated, and 

 ■cultivated, while those to which it is believed that typhoid fever, 

 ■erysipelas, and various other infectious diseases are due, are at the 

 present time under examination. It is a remarkable fact, and one 

 -to which I have already alluded, that with all infecti us illnesses, 

 i.e., those caused by poisonous germs, that one attack, be it ever 

 so slight, has usually the effect of conferring immunity from a 

 recurrence of the same malady. Hence, inoculation with the 

 weakened virus of an infectious disease may be considered a 



