DISEASE 



1804 



DISEASE 



discus sweeps through the air. A distance of 

 140 feet is a fair average for a trained athlete 

 to make in throwing the discus. There is little 

 or no danger of a beginner tiring himself or 



subjecting himself to undue strain by constant 

 practice, and an expert can hurl the discus all 

 day without becoming tired. It is therefore an 

 exercise that has much to commend it. 



ISEASE, dizcez', a 

 state of ill health not caused by 

 old age. It exists among all forms of 

 life, both animal and vegetable. The natural 

 and normal state of any living thing is good 

 health, when all the organs are in good condi- 

 tion and perform their functions in a normal 

 way. An abnormal state, or ill health, exists 

 either when the actual tissues of an organ are 

 affected or when the organ is unable to work 



properly. Diseases, therefore, are 

 roughly classed as organic and func- 

 tional. In organic diseases, such as 

 appendicitis or tuberculosis, the tissues of the 

 organ become diseased and in course of time 

 may degenerate; in functional disease, such as 

 measles and nearly all other fevers, the or- 

 gans are disturbed as the result of changes 

 elsewhere. Frequently organic and functional 

 disorders exist side by side. 



Disease in the Human Body 



Modern medicine divides the causes of dis- 

 ease into two groups; first, those which exist 

 in the body, and second, those which are ex- 

 ternal. Primitive people always believed that 

 disease was caused by external agencies. Their 

 beliefs seem strange and often fantastic to us. 

 The American Indians, for example, thought 

 that disease was simply a manifestation of an 

 evil spirit; they usually tried to frighten away 

 the spirit by noise or by charms and incanta- 

 tions. Their medicine-man was supposed to be 

 particularly endowed by the gods and to have 

 great influence with the spirits. In our own 

 day there are schools of science which regard 

 disease as evil, and as curable either wholly 

 or in part by will power or external mental 

 influence. 



During the Middle Ages, and indeed until 

 comparatively-recent times, many diseases were 

 believed due to an excess of blood, and the 

 most common remedy was to let some of the 

 blood run out of the body. Ordinarily the 

 sicker the person was, the more blood he had 

 to lose a principle which saved few lives. In 

 the course of time all disease was recognized 

 as due to natural causes, but the nature of 

 these and their treatment is still a matter of 

 controversy. For further details, see MEDICINE 

 AND DRUGS. ' 



Germ Theory of Disease. As early as the 



seventeenth century the theory was suggested 

 that disease was sometimes caused by the en- 

 trance of foreign organisms into the body. It 

 was not until about 1876, however, that the 

 experiments of Koch, Pasteur, Tyndall and 

 others established the fact beyond dispute. 



According to the accepted theory, many dis- 

 eases are caused by germs, which are minute 

 organisms of a vegetable nature. This curious 

 fact is usually misunderstood ; germs are a form 

 . of vegetable life, not of animal life. The tiny 

 organisms, which enter the body in a number 

 of ways, cause chemical changes. These 

 changes in turn produce poisons which cause 

 the obvious signs of disease, such as fever, 

 delirium, depression, nausea and convulsions. 

 The poisons also prevent the organs from work- 

 ing properly and thus cause disease. To prove 

 positively that a disease is caused by germs 

 it is necessary to prove three facts: 



(1) A certain germ must always be found In 

 connection with the disease in question. 



(2) It should not, as a general thing; be found 

 in other diseases. 



(3) It must be possible to make a pure culture 

 that is, to grow this germ entirely apart from 

 any other germs. This culture must be able to 

 inoculate animals with the disease. 



The most important diseases that have been 

 proved to be germ diseases ar anthrax, diph- 

 theria, influenza, leprosy, meningitis, pneu- 





