PHENOMENA OF INFECTION. 85 



varieties, namely, (i) bacillary dysentery, due to a 

 bacillus (bacillus dysentericE, Shiga), the other, (2) 

 amoebic dysentery, due to the amoeba dysenterice, an 

 animal organism. Next in importance to these infec- 

 tions are various disorders resulting from animal para- 

 sites. By exercising great caution in the matter of food 

 and drink, one may avoid the infectious and parasitic 

 intestinal disorders, if he cannot those solely dependent 

 upon climate. From the latter, too, it is not impossible 

 to escape, if one abstains entirely from alcoholics and 

 other excesses which tend to increase the amount of 

 blood in organs already overfilled, and if occasional 

 visits to cooler climates be made. The most rigid 

 adherence to the laws of health, combined with such 

 as are especially adapted to a hot country, must be 

 followed. These measures if carried out, and provided 

 the individual is free from disease in the beginning, 

 will ensure the same average health in a tropical as in 

 a temperate country. 



The degree of warmth, the amount of 

 Physical moisture, and the physical conditions of a 

 Conditions, country, all have a bearing upon predis- 

 position, because they supply an essential 

 environment for the perpetuation of forms of life which 

 either cause disease, or transmit it. Besides the vege- 

 table micro-organisms, bacteria and moulds, there are 

 other microscopic and larger forms of life belonging to 

 the animal kingdom which produce disease. Among 



