TYPHOID BACILLUS 1 53 



if the reaction comes within an hour the disease is considered typhoid 

 fever. The test may be either with a hanging drop and examined 

 microscopically, or macro scopically by adding a drop of diluted 

 serum to fresh bouillon culture of typhoid bacilli, when, if the case 

 is typhoid, large clumps of the bacilli will form and drop to the 

 bottom of the tube. Animals immunized against typhoid exhibit 

 this reaction to a high degree. Serum diluted with 10,000 parts 

 of water has caused the reaction in less than one hour's time. This 

 reaction with a known culture of typhoid bacilli is used clinically 

 to identify serum from a doubtful case of typhoid, and establish a 

 diagnosis. On the other hand, a known serum prepared artificially 

 by immunizing rabbits with bacilli is used to identify typhoid bacilli 

 when found in water, or elsewhere. The fetus of a woman suffering 

 from typhoid contains agglutinins in its blood. The milk, tears, 

 and other body fluids from an individual with typhoid, agglutinate 

 typhoid bacilli. Serum to perform the test may be obtained by 

 puncturing the skin, or by blistering it and drawing off the serum, 

 or else by abstracting blood from a vein with a hypodermic 

 syringe. 



Agglutinin appears during typhoid, generally after the fifth day, 

 and persists for some time (several years?) after convalescence. 



There are two stages to the reaction; immediately after mixing 

 the serum and culture, the bacilli will be seen to become less motile, 

 and then still. After this they begin to huddle together into clumps. 

 In complete reaction they remain immobile and tightly massed. 

 In some cases bacteriolysis occurs, and many of the bacteria are 

 dissolved in the serum. It is still uncertain whether the reaction 

 is merely a phenomenon of infection, or whether it has to do with 

 immunity. By many it is held that the two are distinct and separate 

 and that it is a phenomenon of infection. There are several reasons 

 for thinking so. i. The bactericidal action of serum is destroyed 

 at 56 C. The agglutinating power is not destroyed at 62 C. 2. 

 A serum may be bactericidal, but not agglutinative. 3. Bacteria 

 treated with bactericidal sera lose their virulence, and those that 



