PATHOGENIC BACTERIA. 119 



The agglutinating properties have been found in nearly all 

 the secretions of the body tears, urine, milk, pleuritic effusions, 

 serous fluid from blisters, etc. 



There is no relation between the reaction and the bactericidal 

 power of the serum ; the agglutination is not a destruction. The 

 agglutinating power is active, though the blood be dried and 

 sealed up for months. It seems to have no direct relation with 

 the question of immunity, since it occurs at the height of the 

 disease, and intense agglutinating serum may be had in severe 

 cases and in cases with relapses. A negative result does not 

 exclude typhoid. 



The test is quantitative i. e., it depends upon the dilution of 

 the blood-serum, since the serum of healthy persons in strong 

 dilution will cause agglutination and loss of mobility. 



The test must occur within a certain limit of time to be of 

 value, since agglutination is liable to appear of itself with non- 

 typhoid sera after a period of an hour. 



As a clinical test of the disease it has considerable value, 

 although operative at a time when other symptoms have devel- 

 oped sufficiently to determine the diagnosis. 



Staining. Colored with the ordinary aniline dyes, when they 

 are warmed; since they are easily decolorized, acids should be 

 avoided. 



Grain's method is not applicable. Tissue sections stained as 

 follows : 



Alkaline methylin-blue . .1 hour. 



Alcohol 5 seconds. 



Aniline oil 5 minutes. 



Turpentine oil 1 minute. 



Xylol and Canada bals. 



Such a specimen should first be examined with low power, to 

 focus little colored masses, then examined with immersion lens ; 

 these masses will be found composed of bacilli. 



Similar Bacteria. The Neapolitanus bacillus of Emmerich, or 

 f&ces bacillus of Brieger, resembles the typhoid bacillus in many 

 ways, the colonies being the same and its structure similar. 

 But the growth on potato is very different; a thick, yellow, 

 pasty layer is formed thereon. 



