PRINCIPLES OF VETERINARY SURGERY 91 



bacteriological investigation becomes the essential and often 

 the only means of arriving at any definite conclusions. 



DEFINITION. — A bacterium is a minute, unicellular 

 thallophyte (a vegetable vi^ithout a distinct root, stem or 

 leaf). Gould defines bacterium as "a genus of schizomycetous 

 fungi (fission fungi) characterized by short, linear, inflex- 

 ible, rod-like forms. The word 'bacteria,' as now employed, 

 is practically synonymous with schizomycetes, micro-organ- 

 isms, and microbes." More recently the exactness of includ- 

 ing the bacteria among the fungi has been questioned, owing 

 to the fact that some of them contain chlorophyl, and are 

 therefore neither algae nor fungi, but belong to a group by 

 themselves. The classification of bacteria with fungi is re- 

 garded by botanists as purely an arbitrary one. 



DISTRIBUTION. — Bacteria have an exceedingly wide 

 distribution throughout the world. They are almost every- 

 where. They are found in food, water, dust, clothing, soil, 

 tools, utensils, instruments, animal feeds, vegetables, dust of 

 dwellings and stables, street dirt, the surface and the open 

 cavities of the animal body, diseased organs and tissues with- 

 in the body, the excrement of man and animals, etc., etc. In 

 fact, everything external harbors them and very frequently 

 they find their way into the remotest "recesses of things ani- 

 mate and inanimate. 



On the living healthy body of domestic animals micro- 

 organisms are found in abundance, on and within the recesses 

 of the skin, in the mouth, pharynx, stomach and intestines. 

 These organs are capable of harboring pathogenic micro- 

 organisms that are ever ready to produce serious derange- 

 ment when the proper opportunity presents itself. The . 

 respiratory tract always contains micro-organisms that under 

 ordinary conditions of health are harmless, but which are 

 capable of generating a serious morbid phenomenon if the 

 tissues harboring them become weakened from any cause. 



