WALTER SORRELL AND ERED. C. CATER. 
2i)S 
is only temporary, and will be of little value in warding off an 
attack of the disease six or eight months later; also the delay of 
eight days may cause considerable loss, allowing the malady to 
develop in all exposed animals. 
2. The Dehbrinated Blood Method consists in taking blood 
from an animal that has just recovered from the disease, de- 
fibrinating it all with proper aseptic precautions and injecting 
50 c.c. subcutaneously, or in some instances more. 
This has the advantage in that it can be carried on immedi¬ 
ately and renders the animal so treated passively immune; thus 
it may retard more members of the herd from becoming sick; 
also there is no reaction to lower the vitality of the animal and 
allow other troubles to develop. 
The main disadvantages are that in the subjects immunity 
is only temporary, (one to three months) and the danger of 
injecting into the system other infections, thus doing a harm 
instead of a benefit. 
3. The Serum-Simultaneous Method, with a slight modi¬ 
fication, was the one used at the serum laboratory and also in 
some provinces of the islands; it consists in inoculating the indi¬ 
vidual with 50 c.c. of serum and I c.c. of virulent blood on either 
side of the neck or shoulder; in practice this method was modi¬ 
fied to allow the virulent blood to be inoculated ten days after 
the serum, thus giving the system time to take up the serum and 
the immunity to become effective to some extent, as we had no 
adequate method of determining the possibility of the animal 
having been infected naturally, in which case, by the simul¬ 
taneous method, the additional amount of virus would only 
hasten the onset of the disease before the serum could become 
effective, thus causing a higher mortality than we should have. 
In typical reactions the temperature should rise to 40° or 41 0 C. 
on third or fourth day following the virulent blood inoculation, 
and should remain above 40° C. for at least three days. When 
it returns to normal gradually, and although the only visible 
symptoms may be the congestion of the conjunctiva and some 
tearing, more severe symptoms are common, varying with indi¬ 
viduals and their susceptibility. 
