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II. 
TUBERCULOSIS. 
Ty an 
Nature of the Disease. 
tah This disease, technically known by the term tuberculosis, or tubercle, is so-called Nomencla- 
because it produces in the tissues of most warm-blooded animals small inflammatory te. 
lumps or knots, the Latin word for which, as originally applied by Celsus, was 
‘« Tuberculum.” 
2. The disease is known in the United Kingdom by different names, according to 
the parts of the body it may happen to attack, or according to the kind of lesions it 
produces, or finally according to its general effect on the body. ‘Thus, it is commonly 
called phthisis or consumption, pining, and wasting (the animal being called a “ waster’), 
scrofula, strwmous disease, cheesy inflammation of the lungs, caseous pneumonia, caseous 
broncho-pnewmonia, tubercular pleurisy, the grapes, the grape disease (German perlsucht), 
consumption of the bowels, tabes mesenterica, tubercular meningitis. 
3. For many years most of these conditions were supposed to be different diseases ; 
we now know for certain that they are all forms of one’ and the same process, and 
caused by a microbe, %.¢., a parasitic micro-organism, which, growing in the tissues, 
ig rise to the tubercles, and which, by reason of its being thrown off from the 
iseased animal in quantity, renders the malady a contagious one. 
= Tuberculosis, therefore, exists only in those localities where the microbe happens 
to be endemic, that is, however, in all European countries, and can only occur in an 
animal by reason of the microbe being introduced into its system., The microbe, or 
bacillus, thus forms the poison or virus of the disease. 
4. The great discovery that the tubercles or foci of the disease contained a virus 
or poison capable of producing the malady when inoculated into the lower animals 
was first made by Klencke in 1843, but first described at length and placed on an 
undeniably firm basis by Villemin in 1865. The nature of the poison itself remained 
unknown until it was discovered by Koch, in 1881, to be a rod-shaped microbe.: 
5. He found that this rod-shaped microbe was of a length* about equal to or less 
than the diameter of a red-blooded corpuscle. When magnified very highly and stained 
with certain dyes, it presents a dotted appearance, showing that the protoplasm 
forming its body is interrupted. This condition of the protoplasm is supposed further 
to-indicate its reproduction by spores or seeds, such seeds or spores of microbes having, 
it is well known, greater vitality that the adult rod. 
6. This greater vitality of the spore, and the viability of the rods are, of course, 
points of the utmost importance, since, if the mucus, or saliva, or expectoration of an 
animal or human being suffering from tuberculosis be dropped upon the ground, 
flooring, or furniture of a room or shed, it is obvious that such secretions are, in pro- 
portion to the effect which exposure at the temperature of the air and drying may 
have in destroying the organisms and their spores, a source of danger to other animals 
or human beings who may accidentally take up the poison. From this it follows 
that the temperature of the air and drying for a very long period determine the 
survival or death of the infective microbes. These points, therefore, require careful 
consideration and examination. é 
7. The temperature which is most favourable to the growth of the microbe is that 
_ of the ordinary heat of the body of a warm-blooded animal, namely, from 37° to 
38° C. = from about 98°5° to 100°5° Fahrenheit, but if the temperature falls to about 
82° Fahrenheit such growth ceases. Though, however, cold thus prevents its develop- 
ment, it does not kill it, whereas if it be kept at a temperature of about 107°5° 
Fahrenheit for several weeks the organism gradually becomes exhausted and dies. 
8. It is obvious from these facts that, if bacilli or their spores be scattered on the 
; ground or elsewhere at the ordinary temperature of the outer air in our climate, 
* Some very slight differences have been shown to exist in the dimensions and the distribution in the body 
of the bacilli tuberculosis found in the human and bovine disease respectively. All authorities regard these 
differences to be due to the difference of soil in the two cases, and that no difference in the nature of the 
organism is thereby indicated. 
eg 
Vitality and 
power of 
resistance of 
the microbe. 
