BY JOHN THOMSON, M.B. 75 
famous by discovering the Tubercle Bacillus—the germ of 
consumption—provides the answer by insisting that certain 
postulates must be proven before a micro-organism can be 
accepted as the author of any particular ailment. 
1. The micro-organism must be found in the blood, 
lymph, or diseased tissue of the man or animal suffering from, 
or dead of, the disease. 
2. The micro-organism must be isolated from these 
media, and artificially cultivated outside the animal body, 
and these cultivations must be carried on through successive 
generations, and the purity of them maintained. 
3. The micro-organism thus obtained, after generations 
of pure culture, must. when introduced into the body of a 
healthy animal, capable of taking the disease, produce the 
disease in question. 
4. The micro-organism must be again found in the in- 
oculated animal, and in greater number, showing it has 
proliferated. 
And quite a number of diseases, from about twenty- 
seven to thirty, have complied with the requirements, and are 
accepted as of established Bacteriology. 
The term Bacteriology includes much more than the 
derivation of the word warrants. It should refer only to the 
study of Bacteria—vegetable micro-organisms—but usage 
and consent include in it all the morbiferous germs, and 
some of these belong to the Protozoa—to animal life. 
Bacteria are unicellular vegetable growths, devoid of 
chlorophyll, and multiplying by cleavage—fission—hence 
the more scientific name—Schizomycetes or Fission-fungi. 
They can be cultivated much as the plants in a garden, 
and under favourable conditions—of suitable soil, nutrient 
medium, as it is called; moisture; temperature ; light or 
darkness ; oxygen (air) or the want of it—can be made to 
flourish luxuriantly ; yield brilliant colours; emit odours, 
never fragrant odours, usually stenches most abominably 
objectionable and generate deadly poisons. 
