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PREFACE. 



The following pages are intended to convey to the 

 reader a concise account of the technical procedures 

 necessary in the study of bacteriology, a brief descrip- 

 tion of the life-history of the important pathogenic 

 bacteria, and sufficient description of the pathological 

 lesions accompanying the micro-organismal invasions 

 to give an idea of the origin of symptoms and the 

 causes of death. 



The work being upon Pathogenic Bacteria, it does 

 not cover the whole scope of parasitology, and the 

 parasites of higher orders are all omitted. Malaria and 

 amebic dysentery are omitted as logically as tape-worms 

 and pediculi. The higher fungi are also omitted, both 

 because they are not bacteria and because their proper 

 consideration would make a small book in itself. 



In leaving out the non-pathogenic bacteria of course 

 a stumbling-block was encountered. The Sarciua ven- 

 triculi, for instance, may be a cause of dyspepsia, yet 

 can scarcely be regarded as pathogenic, and, together 

 with other similar bacteria of questionable deleterious 

 operation, has been omitted ; on the other hand, it 

 has been thought advisable to include and describe 

 somewhat at length a long list of spirilla similar to, 

 and probably closely allied with, the spirillum of 

 cholera, yet not the cause of any particular diseased 

 condition. 



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