AGGLUTININS. 



209 



agglutinable strain gives a strong agglutinin. The 

 logic of this will become apparent when we con- 

 sider the nature of the bacterial substance which 

 causes the body to produce agglutinin. 



That the agglutinating power of the serum of a 

 typhoid patient varies from day to day is a fact 

 of practical importance. It may be thirty times as 

 strong one day as the next., and may even disap- 

 pear entirely for a day or two. Hence the impor- 

 tance of making more than one test in a suspicious 

 case,, when the first trial has been doubtful or 

 negative. There is no adequate explanation for 

 this great variation. It is said that mixed infec- 

 tions, intestinal hemorrhage, or a sudden pouring 

 out of typhoid bacilli into the circulation may 

 cause a reduction in the agglutinating power. This 

 occurrence has an important bearing on the possi- 

 bility of using the agglutinating power of the 

 serum as a prognostic sign. Although it has often 

 been noted that in fatal infections agglutinins may 

 be absent from the serum, the variations just men- 

 tioned indicate that prognosis could not be based 

 safely on the result of a single agglutination test. 



The agglutinating substance is found in the 

 highest concentration in the blood serum, but it 

 may be demonstrated in the various body fluids 

 and in extracts of the organs ; it is said to be par- 

 ticularly rich in the milk. It is present in the 

 serum of an artificially produced blister, and it has 

 been recommended that blistering be resorted to 

 in order to obtain serum for the test. The bile 

 often agglutinates the typhoid bacillus, but the 

 power has no necessary relationship to a pre-exist- 

 ing infection ; it is possible that the agglutination 

 this case is due to obscure chemical causes 



Variations in 

 Quantity of 

 Agglutinins. 



Distribution 

 of Agglutin- 

 ins in Body. 



m 



