THE VEGETABLE PARASITES. 41 



Rest. — Some fungi flourish better in a still medium than 

 in one constantly agitated. Bacillus Anthracis divides 

 actively in the circulating blood, whereas other forms seem 

 to settle before so doing. 



Clinically, two great divisions of organisms are recog- 

 nised : (1) The pathogenic, which can invade living tissue, 

 and by their growth there almost always cause disease ; 

 (2) The non-pathogenic, which can only grow in dead 

 tissue. Bacterium Termo, the cause of putrefaction, is the 

 most important of these. 



Infective diseases are divided, according to certain 

 characteristics of the virus, into : 



1. Contagious. — These are communicable from individual 

 to individual, and are frequently epidemic. The virus runs 

 its whole course of development in the body. 



2. Miasmatic. — These are endemic diseases, of which 

 malarial fever is an example. The poison which causes 

 these diseases is developed outside the body. 



3. Contagio-Miasmatic. — In these the poison has to 

 undergo some change external to the body, and the diseases 

 seem to be always derived indirectly from a previous case 

 of the malady. As an example, cholera may be given. 



4. Septic. — The poisons of these may be derived from 

 many putrid infusions. "When once thus started, the 

 disease can be transmitted directly from individual to 

 individual. 



The Bacillus Anthracis is the best known of all the endo- 

 parasitic fungi. As this germ is the cause of splenic fever 

 of cattle, anthrax of the horse, and malignant pustule of 

 man, it will be well to give a short outline of its distinguish- 

 ing features and conditions of life, as well as of Pasteur's 

 method of inoculating animals by the attenuated organism 

 as a preventive against future invasion. In the blood 

 from the enlarged spleen of animals dead of splenic fever are 



