PATHOGENESIS AND DEVELOPMENT OF DISEASE. 
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experiments on this question, as well as the culture researches in 
connection with the organisms of disease. Dr. Budd, in 1849, 
claimed the body was invaded by organisms which under certain 
conditions and surroundings caused infectious diseases. It is of 
late years, in fact since ’70, that we have been shown the relation 
of micro-organisms to those diseases which most closely interest 
the veterinarian—as anthrax, septicaemia, cholera in its vari¬ 
ous forms, lupus, glanders, rabies, pleuro-pneumonia, favus and 
the greatest of all scourges, tuberculosis. Koch and Pasteur 
have done much in the latter years to enlighten us upon this 
subject. The satisfying of all, the requirements essential to 
prove a germ indigenous to a disease is difficult and has led to 
what may be termed a special branch of medical art. 
Brefalo has observed that bacterium may divide once 
every half hour and its progeny repeat the process in the same 
time, thus producing in 24 hours segments amounting to many 
million spores or resting cells ; these are the smallest segments or 
cocci into which the filament at length breaks up. Yet it is 
questionable whether the bacteria suspended in the air are so 
plentiful as was once supposed. Formerly the great difficulty 
seemed to lie in distinguishing accurately between a germ and 
spore, the words being used in an indefinite sense. A germ is the 
first principle of anything that has life whether animal or vege¬ 
table, a growing point from which the life and organization of 
the future plant are to spring, while a spore is a fecundated 
seed of a lower organism, and though it may be practically con¬ 
sidered the originator of a disease, in a true sense it cannot be, for 
the elements of which it is composed derive some consideration. 
Yet if the pre-existing spore is not present it then becomes most 
difficult to account for the minute infusoria found swarming 
fully developed in putrefying fluid or flesh—in themselves 
scientifically healthy, though not rendered antiseptic, though they 
may be placed in antiseptic surroundings. It has been frequently 
shown that pure culture of fungi grown on gelatine, decompose, 
and the fluid in which they are soon swarms with bacteria. 
The fungi being so minute we have little time knowledge of 
