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204 QUEENSLAND AGRICULTURAL JOURNAL. [1 Mar., 1899. 
of a diseased animal be examined a little before or immediately after death, the 
vegetative rods of Bacillus anthracis are easily found by means of a suitable 
microscope. Now if the smallest quantity of such blood is introduced 
into the tissues of another animal capable of taking the disease, the 
inoculated animal becomes infected and almost certainly succumbs; and 
if the blood of the second animal be similarly examined this also will 
be found densely populated with the same bacilli. We thus see that the 
disease is accompanied by the enormous multiplication of the micro- 
organisms within the system of the infected animal, and that the disease 
may be indefinitely communicated from one animal to another; but we may also: 
cause this bacillus to grow and multiply outside the animal system altogether, 
or, as we term it, cultivate the organism in an artificial medium. Thus, if we 
take on the point of a sterilised platinum needle the merest trace of blood of 
an animal just dead of anthrax, and then introduce the point of the needle into: 
any of the ordinary cultivating media, such as broth, gelatine, agargar, and 
blood-serum, or even the surface of a boiled potato, we shall obtain in the: 
course of a few days an abundant growth of the anthrax bacillus, readily visible 
to the naked eye and presenting a most characteristic growth. On micro- 
scopical examination we find that this peculiar wool-like growth is made up of 
bacilli held end to end in a delicate filamentous sheath. By continual micro- 
scopical examination of these filaments we shall notice that a number of extra- 
ordinary changes are brought about; the contents of each individua) segment 
or bacillus in the filaments sooner or later become granular; at a later stage a 
very minute speck appears in the centre of each rod. These bright, highly 
refractile bodies are the so-called spores, which, in consequence of the greater: 
power of resisting destruction, are of such importance in the propagation of this. 
dreaded disease. In the blood of the subject affected, these anthrax bacilli are 
not able to form spores, but outside the body they give rise abundantly to these 
indestructible forms, and it is this power of producing spores which renders. 
this organism so dangerous and persistent. Thus, if the carcasses of animals 
dead of anthrax are lightly buried or allowed to decay on the surface of the 
earth, the bacilli form spores in the soil, and healthy animals may thus become 
infected by taking the spores with their food when grazing. Again, the skin 
of animals which have died of anthrax in some countries, especially Russia, not 
infrequently pass into commerce, and often prove fatal to the tanners and wool- 
sorters who handle them even long afterwards. To give you some idea how 
tenacious of life and resistent these minute spores are, and how they 
retain their virulent properties, I have with me this evening a little bottle: 
containing some silk threads which I impregnated with anthrax spores in May, 
1886, nearly twelve years ago. In the first three successive winters in London 
they stood in a cupboard where the temperature was considerably below freezing 
point for several days, but since that time they have been kept ina moderately 
temperate atmosphere, but always in a desiccated condition. From time to time: 
I test the virulence of these spores by placing a little piece of thread under the 
skin of a guinea pig, which results in the death of the animal (without any 
exception whateyer), within twenty-four hours, of virulent anthrax. More- 
over, on microscopical examination of a merest trace of blood taken from the: 
spleen, the anthrax bacilli are readily demonstrated in large numbers. This 
experiment illustrates very clearly how the spores of the anthrax bacilli may 
get into the soil, and may remain there in a dormant state for many years.. 
Anthrax has been known to break out among cattle grazing on a field where: 
several years previously some Russian hides from infected animals had been 
buried. By some means or other the spores may contaminate the grass and 
hay imported from an anthrax-infected district, and may start the disease on a. 
farm on which it had never been known to occur. The spores may be conveyed 
in a similar way with blood manure and bone manure, or with refuse used for 
manure. The skin, hair, wool, hoofs, and horns of infected animals, if soiled with 
blood, are contaminated by the bacillus. Bearing all these facts in mind, it will 
be seen how necessary it is that the strictest supervision should be exercised. 
