1 Sepr., 1899.] QUEENSLAND AGRICULTURAL JOURNAL. 307 
The invasion of the animal’s bod 
y by the entrance into it of living bacilli is 
effected either through the digestive 
organs (ingestion) or by the respiratory 
organs (inhalation), by transmission to the sexual organs when the testicle ig 
invaded, and by inoculation, or by a cut or abraded surface. 
Without the entrance of the living bacillus into the body, tuberculosis 
cannot affect it. It is the seed from which it grows, and it as essential to the 
development of the disease as oats, peas, or potatoes are to reproduce these 
plants. 
WHAT RENDERS CATTLE SUSCEPTIBLE TO THIS DISEASE? 
Impaired health, from whatever cause it arises, renders cattle susceptible to 
tuberculosis. Heredity has been proved not to be an active cause of its 
papheeation ; it is, however, a predisposing one, and while it is well established, 
y the experiments of Professor Bang and others, that calyes may be bred from 
tuberculous mothers, and if removed before the cow licks them, or they have 
sucked their mother’s milk, are placed in absolutely healthy surrounding and 
fed on milk from healthy cows, they can be reared and remain, so far as any 
inherited disease is concerned, perfectly free ; but common sense will teach us 
that in such animals we are likely to find a pr 
edisposition—that is, a condition 
favourable to the growth and development of the tubercular bacillus: animals 
likely to contract the disease when exposed to contagion which their neighbours 
not so predisposed would resist successfully. 
In-and-in breeding is another predisposing cause, by producing animals 
with reduced vitality. Over-milking, under-feeding, want of sunlicht and pure 
air, insufficient exercise, breeding too young, are all what may be termed predis- 
posing causes to tuberculosis, and should be avoided. 
One breed of cattle is just as subject to this disease as another, when sub- 
jected to the predisposing and exciting causes. Dairy cattle are most subject 
to it because they are most exposed, they are more congregated, more closely 
and continuously housed, their vitality more drained by heavy milking, and they 
are kept longer. Their calves are more liable to milk infection, as they are fed 
on mixed milk, whereas the beef breeds usual 
d ly suckle their calyés. The 
majority of beef cattle are killed off at three or 
four years old; hence they are 
exposed to the contagion for a shorter term of life, which is spent more in the 
open air and in sunlight. 
HOW THE DISEASE IS USUALLY INTRODUCED IN 
IT EXTENDS IN TT. 
A. tuberculous bull is probably the most active agent in spreading this 
disease, both by cohabitation and sexual connection. 
Farmers cannot be over-cautious in buying a bull or in having cows served 
by one till he has been subjected to the tuberculin test and found to be free 
from the disease. 
Nothing should induce a breeder to allow contact with his healthy cattle 
by a bull till he has every assurance that he is free f 
° : rom tuberculosis. , 
Tuberculous animals of any kind should be prevented from coming in 
contact with the cattle. 
TO A HERD, AND HOW 
TUBERCULOUS ATTENDAN TS. 
Tuberculous attendants—men or women suff 
sumption—should on no account be allowed to feed, 
with cattle or pigs. 
The intercommunicability of the disease from 
4 animals to man and from man 
to animals is an established fact no longer open to discussion. 
The bacilli from the throats and lungs of diseased people or animals, being 
coughed up, adhere to and dry on the woodwork, walls, floors, ‘and feed-boxes in 
buildings, cattle-trucks, or stockyards, and the dust being moved about by air 
currents, or mixing with the food in the hay-rack or feed-trough, finds access to 
the stomach and intestines; thence through the blood or lymph channels to the 
abdominal glands and other organs. 
ering from pulmonary con- 
milk, or have anything to do 
