34 CLINICAL BACTERIOLOGY. 



materies morbi from the sick to the well. With the latter, 

 the disease- virus, the miasm, is taken up only from the air, 

 or, in general, from surrounding nature ; the miasmatic dis- 

 eases are never transmitted from individual to individual. 

 This division has now lost much of its significance. Most 

 infectious diseases with whose causative agents we are 

 familiar are contagious-miasmatic that is, they are trans- 

 mitted as well from one person to another as from without, 

 through the intermediation of the air, the water, etc. Even 

 malaria may no longer be considered a strictly miasmatic 

 infection, although under natural conditions it is probably 

 never communicated from one person to another, since Ger- 

 hardt has transmitted the disease from a malarial patient to 

 a healthy person by blood-transfusion. 



According to the activity of their causative bacteria, in- 

 fections may be divided into toxic and infectious* In the 

 former the manifestations caused directly by the living 

 germ that is, the local symptoms at the site of infection 

 are subordinate to the toxic manifestations those result- 

 ing from absorption of the poisonous substances generated 

 by the bacteria. As examples of such toxic infections may 

 be mentioned experimental diphtheria in animals, and in 

 man especially tetanus, the local manifestation of which 

 often consists only in slight suppuration, or is entirely ab- 

 sent, so that the site of infection frequently escapes detec- 

 tion. On the other hand, in the infectious diseases the 

 disease -germs themselves play the most important role, 

 acting especially through their enormous multiplication. 

 If this takes place throughout the entire body by way of the 

 blood-stream, the condition is designated septicemia. The 

 type of such a condition is anthrax, in which, no matter in 

 what situation the infection took place, the bacillus may be 

 found present everywhere in every organ and in every 

 tissue. 



Examples of infectious diseases in a restricted sense are, 

 in man, for instance, cholera and pneumonia, in which enor- 

 mous multiplication of the causative agents takes place 

 within a circumscribed area (intestine or lung), and the 

 local symptoms are very considerable. Just these two in- 



* This nomenclature is awkward and tautologic. The differences intended 

 to be expressed are of degree and not of kind. All of the diseases of this 

 group are infectious, naturally in varying grade, and all give rise tQ secondary 

 intoxication, also of varying grade. A. A. E. 



