BACTERIA IN THE SOIL 1/7 



abnormally, in the soil. But closely allied to these matters 

 connected with the role of pathogenic bacteria in soil is the 

 question of what has been termed the miasmatic influence 

 of soil. The term '* miasm *' has had an extensive and 

 somewhat diffuse application in medical science. It may 

 happen in the future that typhoid will be classified strictly 

 as a miasmatic disease. But at present, in the transition 

 state of the science, it would hardly be justifiable to classify 

 typhoid with a typically miasmatic disease like malaria. 

 Yet it is clear that mention should here be made of a group 

 of diseases of which malaria is the type, and of which the 

 tropics generally are the native land. The bacterial etiology 

 of the group is by no means worked out. The cause of 

 malaria alone is not yet a closed subject. However the de- 

 tails of the etiology of this group finally arrange themselves, 

 there is little doubt of two facts, viz., the diseases are prob- 

 ably produced by bacteria or allied protozoa, and soil plays 

 an important part in their production. 



From what has been said, it will be seen that though a 

 considerable amount of knowledge has been obtained re- 

 specting bacteria in the soil, it may be conjectured that 

 actually there is still a great deal to ascertain before the 

 micro-biology of soil is in any measure complete or even 

 intelligent. The mere mention of tetanus and typhoid in the 

 soil, and their habits, nutriment, and products therein, not 

 to mention the work of the economic bacteria, is to open up 

 to the scientific mind a vast realm of possibility. It is 

 scarcely too much to say that a fuller knowledge of the part 

 which soil plays in the culture and propagation of bacteria 

 may suffice to revolutionise the practice of preventive medi- 

 cine. Truly, our knowledge at the moment is rather a 

 heterogeneous collection of isolated facts and theories, some 

 of which, at all events, require ample confirmation ; still, 

 there is a basis for the future which promises much con- 

 structive work. 



