TRANSACTIONS OF SECTION I, 543 
contact, No experiments have, as far as I am aware, been made as to whether it 
is conveyed by insects as well ; but, as Professor John MacTadyean says, as it spreads 
in all countries and climates and seasons, and the contagium is easily carried on 
the persons or clothes of human beings, it is improbable that insects have anything 
to do with it. 
It is in the methods of protective inoculation that the great advance has been 
made in our knowledge of this disease. Ten years ago no means were available to 
stay the progress of this plague ; now it has lost its terrors. Assoon as it appears 
it can be immediately attacked and stamped out. This is done by rendering the 
surrounding cattle immune to the disease by injecting immuneserum. This serum 
is prepared by taking immune cattle and hyper-immunising them by the injection 
of large quantities of virulent blood, so as to male their blood serum as anti-toxic 
as possible. If there are no immune cattle at hand, cattle can be immunised by 
Koch’s bile injection method and then hyper-immunised; but, of course, in 
practice—for example, here in the Transvaal—large quantities of immune serum are 
kept ready for emergencies, and a herd of immune cattle kept up for the supply of 
the serum. This satisfactory state of affairs, as far as this disease is concerned, is, 
of course, the outcome of an immense amount of thought and experiment, and I 
have already mentioned the chief scientific men to whom this country owes this 
great boon. 
Different methods of immunising have been tried during these years. Up to 
1903 the prevailing custom was to use what was known as the virulent-blood and 
serum method. That is to say, immune serum and virulent blood were injected 
at the same time, in order that the animal might pass through a modified attack 
of the disease. Since 1903, however, in the Transvaal this method has been 
stopped, and the ‘serum alone’ method introduced. This method is based on the 
fact that the virus of Rinderpest does not retain its infective property outside the 
body for more than a day or two; that it dies out in the animal, as a rule, in 
fourteen days, but in chronic cases only after thirty days, and that therefore the 
healthy cattle in an affected herd must be protected for this length of time. Now 
‘serum alone’ only protects for about ten days, and therefore the cattle must be 
inoculated three times at intervals of ten days. The doses of serum must also be 
large—from 5U cc. to 200 cc.—so that this method of stamping out Rinderpest, 
although quite efficacious, entails a good deal of labour. It is necessary, then, to 
spare no expense in making the Veterinary Department efficient, and any cheese- 
paring legislation in this direction may be disastrous. 
II, Horse-sickness. 
The next stock plague I would bring before your notice is Horse-sickness. 
This is a disease which only affects equines—the horse, mule, and rarely the 
donkey. It is a very fatal disease, carrying off thousands of horses every year. 
It is one of the most important diseases in South Africa, and, if it could be coped 
with, would enable the Transvaal to become one of the best horse-breeding 
countries in the world. At present it is dangerous for anyone in Natal and many 
parts of the Transvaal to possess a valuable horse, the chances of losing it by 
Horse-sickness being so great. 
In 1895, when I went to the north of Zululand with the Incwavuma Expe- 
dition, we lost all our horses with this disease. We started with a hundred horses, 
and had to march back on foot, every horse having died. 
Ten years ago, when I arrived in South Africa, our knowledge of this disease 
was confined to the disease itself; nothing was known as to its causation or pre- 
vention. Credit is due to Dr. Edington for having accurately described the 
lesions and shown its ready inoculability, period of incubation, &c. He, how- 
he fell into the mistake of attributing its causation to a species of mould 
ungus. 
Etiology: Geographical Distribution —Horse-sickness is widely distributed 
throughout Africa, It is common in Natal, Zululand, the greater part of the 
Transyaal, Rhodesia, Bechuanaland, and Portuguese East Africa. In Cape Colony 
