[ i3 1 
attacks may be so mild that the animal may only appear to be in ill 
health for a day or two and may be able to travel and even to work 
throughout the illness. These animals, usually Indian bullocks, are the 
most dangerous carriers, more so than the Malay buffalo which is usua y 
unfit to travel before the discharges are abundant. These animals show 
little disposition to travel and are so markedly ill that the disease is at 
once detected. . , . • 
Indian Buffalo calves were possibly carriers amongst the adjoining 
herds of cattle at the 2nd mile Batu Road. . . M 
We have no proof how long convalescents can carry infection. Mo 
case of infection could be traced to any of the convalescents discharged. 
Careful watch was maintained. Only few convalescents were allowed out 
of isolation in three weeks, and the majority were kept over a month, often 
much more than a month, so that a convalescent does not convey the disease 
more than three weeks after convalescence. 
Prophylactic use of Serum .—Inoculation with serum prepared locally and 
inoculation combined with simultaneous injection of virulent blood had 
been tried in previous epidemics. The results had not been sufficiently 
conclusive to cause the general adoption of either method. 
There are considerable difficulties in the local preparation of serum, and 
considering the high price of cattle and the expense of a staff for serum w ork 
it was considered cheaper and better to import serum from India. 
Mr. Moir, the Government Veterinary Surgeon, Perak, had been 
using this serum for some time and considered his results as high y 
satisfactory. , r . r j 
Mr. Ford, the Government Veterinary Surgeon, Selangor, first used 
this serum in the Kwala Selangor outbreak and to a very large extent in the 
Kwala Lumpur outbreak. His earlier results seemed to indicate : (1) I he 
cattle already infected had the disease in a milder form and that the per¬ 
centage of recoveries were higher; (2) That animals inoculated previous to 
exposure to infection or which were not already infected did not become 
infected. , . . • 1 
As regards the first of these the more extensive knowledge now gained 
shows that the serum does not appreciably mitigate the severity of the 
disease either in animals infected or in the stage of incubation, and that there 
is no appreciable reduction in the moitalitv. _ . . , , . 
As regards the second, with numerous provisoes and exceptions, it holds 
cr 0 od for a limited period only. 
With Indian bullocks out of 771 of those injected 54 cases, or 7.4 per 
cent., occurred over 10 days after injection though most of them were 
exposed to infection in the next two months. 
The Siamese bullocks gave similar results. Lot only as with the Indian 
bullocks did it have no effect if injected into animals already infected or in 
the incubation stage, but practically the same proportion, 39 out of 610, o 
those injected developed the disease more than 10 days after the injection and, 
therefore, had received the injection before infection occurred. Double the 
proportional dose was given with the Siamese cattle, as in the minimum 
with some groups the effect was so slight, but even with this dose though 
protection seemed to be conferred on some lots of cattle on others it was 
COml lt r appears'that Siamese cattle, really cattle from widely scattered 
countries, vary greatly as to their susceptibility. 
