591 
temporary one in the case of nearly all the others, and that the bile 
could be kept for a year (Edington), eighty-five days (Nicolle and 
Bey), one hundred and sixty-two days (Rogers). The immunity lasts 
for from two weeks to six months (Jobling). 
The disadvantages were that no immunity appeared before the eight- 
centh day, that many animals did not react and that therefore they 
would contract the disease from the blood inoculation and die, that two 
inoculations were needed, and that it was necessary to bleed a sick animal 
to obtain virulent blood. 
COMBINED METILODS OF IMMUNIZATION. 
1, Serum simultaneous method.—This depends upon the fact that when 1 cubic 
centimeter of virulent rinderpest blood is inoculated under the skin of one side 
of the body and a minimal efficient dose of immune serum is injected upon the 
other, the animal so treated experiences a very mild form of the disease and 
recovers. (Chart 13, No. 921.) In 90 per cent of the animals a lasting immunity 
is produced, while upon the 10 per cent in which no reaction occurs, a transient 
immunity is conferred (Kolle and Turner, Refik-Bey, Nicolle and Adil-Bey). 
The advantages of this method are the immediate, permanent im- 
munity produced in the majority of instances, and the transient one in 
the others, more reactions are produced than with the bile method and 
only one inoculation is necessary. 
The disadvantages are found in the losses by death, which vary from 
1 to + per cent (among 9,077 cases in Cape Colony there was a mortality 
of 1.4 per cent), in only temporary immunity in a certain proportion of 
the animals inoculated, in the interference with lactation and pregnancy, 
in the difficulty sometimes experienced in obtaining virulent blood,* and 
in the danger of latent blood diseases (Texas fever, trypanosomiasis, 
foot-and-mouth disease). 
This form of inoculation has been variously modified. Nencki and 
his co-workers, Sieber and Wysnikowitsch, advise giving the serum two 
hours and Hutcheon administering it forty-eight hours after the virulent 
blood, and then to watch the temperature and once more to administer 
serum. . 
2. Deferred virulent blood method—Another modification and one 
which is generally used in our work, is to give the serum a day or several 
days before the virulent blood. (See Chart 14, No. 106.) In using this 
modification we also follow Roger’s suggestion of carefully watching the 
_ temperature of the animals, and, if no reaction occurs after the in- 
oculation, a second inoculation with 10 cubie centimeters (2 cubic cen- 
timeters for calves) of virulent blood is made. This method requires 
*To obviate this last difficulty it has been advised to use sheep to propagate the 
infection, ete. 
