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saving many thousands of liyes. 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 amcebe (from 
their inherent power of changing their shape), and to the infusoria 
met with in stagnant water. Many years ago both amebe 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 of 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 
+o 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 
