DISEASE 



1805 



DISEASE 



monia, infantile paralysis, tetanus, typhoid 

 fever and tuberculosis. There are a few others 

 which have some of the characteristics of germ 

 diseases, but their nature is still in doubt! 

 Among these are measles, smallpox and whoop- 

 ing cough. See BACTERIA AND BACTERIOLOGY. 



Modern investigation seems to point to the 

 fact that every infectious or contagious dis- 

 ease is due to some germ, and that each dis- 

 ease is produced by only one kind of germ. A 

 disease cannot arise until the germ has entered 

 the body. Every germ disease, therefore, must 

 be preceded by another case of the same disease. 

 In this fact lies the hope and the suggestion of 

 a method for lessening, if not of completely 

 exterminating, such diseases. If the particular 

 microbe of each disease is discovered, the 

 conditions which make its further existence 

 possible can be studied. The information 

 gained would make it possible in almost every 

 case to prevent the development of the germs 

 in the body. Even in those diseases which still 

 baffle science, the presence of germs has led 

 to steps for preventing the spread of the dis- 

 ease. Isolation hospitals are the principal 

 means for preventing epidemics, but the use 

 of antiseptics is also noteworthy (see ANTI- 

 SEPTIC). In fact, the discovery that wounds 



and cuts could be saved from infection by 

 cleanliness and antiseptics was one of the great- 

 est advances made by modern medicine. 



Germs in the Human Body. The human 

 body is continually at war with all kinds of 

 germs, and it is only when its defenses are 

 broken down that the germs can attack the 

 interior of the body. The strongest defense 

 that the body has is the skin. Under normal 

 conditions it is practically impossible for a 

 germ to pass through the skin into the body. 

 If, however, there is a cut, or a scratch, or any 

 kind of an abrasion on the skin, there is an 

 easy opening for invasion. 



There are other openings of the body that 

 offer easy access. Most germs enter the system 

 through the mouth, the nose or the eyes. 

 These are all lined with mucous membrane, 

 which is very easily infected. Once the germs 

 do get into the body they usually increase rap- 

 idly in numbers, and unless their growth is 

 checked they destroy the tissues or produce 

 poisons, technically called toxins. The blood 

 can rebuild the tissues, if the person is strong 

 enough, and the white corpuscles in the blood 

 help to destroy the poisons. The blood itself 

 and the pores of the skin also carry off some 

 of the toxic, or poisonous, products. J.H.K. 



Diseases of Animals 



Animals are subject to many of the diseases 

 which afflict man, pneumonia and tuberculosis 

 being prominent among them. Animal dis- 

 eases may be .classed under five heads, as fol- 

 lows: 



1. Infectious Diseases. Among these are an- 

 thrax, cattle plague, dog distemper, hoof and 

 mouth disease, fowl cholera, hog cholera, rabies 

 and tuberculosis. These are generally regarded 

 as the most dangerous of animal diseases, be- 

 cause whole herds may be affected. In many 

 cases the animals die, and in others they must 

 be slaughtered to prevent the spread of epi- 

 demics. The origin and cure of many of these 

 infectious diseases are still unknown, and it is 

 noteworthy that cleanliness and perfect sanita- 

 tion do not prevent them. Special care should 

 be taken to prevent infectious disease among 

 milch cows, because their milk is almost sure 

 to be diseased and to cause sickness among 

 human beings who drink it. 



2. Poison Diseases. Many animals are poi- 

 soned by mineral substances, such as arsenic, 

 copper, lead, phosphorus, mercury and zinc. 

 The result of such poisoning is usually death. 



Then, too, though it may seem strange, there 

 are many plants or plant products which poison 

 animals. Among these are opium, strychnine, 

 hemlock, larkspur and the famous loco-weed. 

 A "locoed" horse, for example, may die or 

 simply run wild and become useless. Snake- 

 bites and bee-stings are also poisonous, to a 

 greater or less degree, to all animals. 



3. Constitutional Diseases. Under this head 

 are classed such diseases as diabetes, scurvy 

 and a few other diseases, all of which also affect 

 human beings. They are far less common than 

 the infectious or poison diseases. 



4. Organic Diseases. This class comprises all 

 diseases, such as pneumonia, which affect the 

 organs. Heart disease and various disorders 

 of the digestive system are common. Some 

 organic diseases are also infectious. 



5. Diseases Due to Parasites. Almost every 

 species of animal, especially when domesticated 

 by man, is subject to the attacks of parasites. 

 Domestic animals usually have worms in larger 

 or smaller numbers, but it is only when they 

 become numerous that their presence affects 

 the general health. Tapeworms cause nodular 



