ill at ee camille 
492 
THE PREPARATION OF A CURATIVE SERUM FOR DYSENTERY. 
In conclusion, a few experiments on the preparation of a curative 
serum, based upon work which has extended over more than a year, will 
be given. In a practical way these experiments are highly important, as 
the bacilli of dysentery occur in various types which, from the standpoint 
of methods of immunization, are considerably removed from one another. 
For technical purposes, were it possible, it would be highly desirable to 
prepare a universal serum which would be active against all of the 
dysentery bacilli, by the treatment of animals with one type of bacillus 
only. Unfortunately, this can not be done. We have already seen that 
the rabbit immune serum from each of the five is to a certain extent 
specific in its agglutinating and bacteriolytic properties, and it is there- 
fore a priort highly improbable that a universal serum could be prepared 
by immunizing with one type only. 
Horses react toward dysentery bacilli very differently from rabbits; 
thus, for example, the horse immune serum produced with the original 
type of bacillus is also more or less effective toward the others, but this 
group reaction is not sufficiently great to be of value for therapeutic 
purposes. In immunizing horses I have several times had unfortunate, 
but instructive, experiences. On one occasion, when the resistance of an 
animal was so high that it could well endure the injection of 25 agar 
cultures of Types I and II, it was given a similar dosage of Type V. 
Hight days thereafter it died of rupture of the liver. A second horse 
received 40 cultures of Type I and IT and after fourteen days 45 agar 
cultures of Type V; thereupon the temperature rapidly rose to 39.4° 
and then quickly fell to below normal. The animal died from collapse 
three days after the injection. These observations seem to show that the 
treatment with Types I and II did not protect against Type V. 
After this disgression I will once more return to my principal subject. 
After I had first shown that the immune serum of the horse, prepared 
either with the original bacillus or one of the varieties, was not active 
against all types, I continued the work with the purpose of ascertaining 
if a universal serum could be obtained by combining the immunizing 
properties of the original type and one of the varieties. For this purpose 
I immunized a number of horses with different combinations of dysentery 
bacilli and then tested the immune serum with the different types. 
The method of testing was as follows: Diminishing quantities of the serum 
were added to the cultures of the dysentery bacilli in five times the fatal doses, 
and the resulting mixtures injected intraperitoneally into mice. A fixed quan- 
tity on an accurately calibrated platinum oese was taken from an incubated 
twenty-four-hour agar culture, suspended in an accurately measured quantity of 
normal salt solution so that 1 cubic centimeter contained exactly 2 milligrams of 
bacilli. The immune serum was added to test tubes in the following quantities: 
0.5, 0.25, 0.1, 0.05, 0.025, 0.01, and 0.005 and all of the tubes were filled to 1 cubic 
centimeter, after which 1 cubie centimeter of the suspension of the bacilli was 
added; 0.4 of this mixture was then injected intraperitoneally into each of two 
mice of 12 to 14 grams weight. As one-fifth of the mixture in the tubes had 
