372 



PHARMACEUTICAL BACTERIOLOGY 



The term epidemic is, however, also applied to any communicable disease 

 which has become general in a given community. A more or less common 

 or spreading disease which is limited to and recurs in a given district or 

 country is said to be endemic in that district or country. Endemics are 

 usually due to climatic conditions which encourage certain microbic and 

 other disease-producing invasions. 



The causes of disease are of two kinds, primary or inciting, and second- 

 ary or predisposing. The primary cause of a disease is that factor or in- 

 fluence which must invariably be active before the disease can possibly 

 develop. For example, the primary cause of diphtheria is the diphtheria 

 bacillus; the predisposing causes are exposure to wet and cold, impover- 

 ished condition of body, etc. No matter how numerous or how active the 

 predisposing causes may be, the disease cannot develop until the primary 

 cause acts. There are numerous abnormal or pathological states or con- 

 ditions without recognizable primary causes, as gout, rheumatism and the 

 senile changes in the body; and again there are certain diseases which 

 evidently have primary causes, as whooping-cough, small-pox and yellow 

 fever, but in which said primary causes are not yet discovered. The 

 following tabulation outlines the primary and secondary causes of disease: 



Bacteria, as in typhoid and Asiatic cholera. 

 Protozoa, as in malaria. 



Primary causes Parasitic higher animals, as tape-worm and 



(inciting). itch. 



Fungi, as in ring-worm and pellagra. 

 Undetermined, as in small-pox. 



Communicable 

 diseases. 



Secondary causes 

 (predisposing). 



[ Race. 1 ._ 



TT j-,. T- -i KPhylogenetic). 



Heredity . . j Family, j v 



[individual (ontogenetic). 



Age. 



Sex. 



Environment. 



Habits. 



Infancy. 

 Childhood. 

 Adolesence. 

 Adult. 

 Old age. 



Climate. 

 Altitude. 

 Seasons. 



Unsuitable food. 

 Unsuitable clothing. 

 Poisons. 

 Occupation. 

 Injuries. 



Alcoholic. 

 Tobacco. 

 Drugs. 



Coffee and tea. 

 I Gourmandage. 



