390 TYPHOID FEVER 



The standard that is adopted varies in different laboratories, but 

 in the great majority of cases it will be found that the serum at 

 the end of the first week will clump in a dilution of i : 30 in one 

 hour at the body temperature, and that this is very seldom the 

 case in health or in other diseases. The amount of agglutinin 

 soon increases, and may reach a degree at which it will agglu- 

 tinate at i : 1,000 or more. The naked-eye reaction as carried out 

 by a modification of Wright's method renders it very easy to 

 perform exact quantitative work, and it is an advantage to do so in 

 all cases in which the agglutination does not reach i : 50 on the 

 first examination, since a rise in the power of the serum is 

 practically diagnostic. My routine method is as follows : A unit 

 mark is made about i inch from the end of a rather wide 

 Wright's pipette, and with this 9, 2, 4 and 9 units of a watery 

 emulsion of a young agar culture of typhoid bacilli are placed in 

 four depressions on a porcelain slab ; dead cultures may also be 

 used in the same way. A unit of serum is now sucked into the 

 pipette and mixed with the first pool of 9 units of emulsion. 

 One unit of this is then mixed with each of the remaining three 

 pools, the process being carried out quickly, so as to avoid the 

 absorption of agglutinin from the powerful serum. This gives a 

 series of i : 10, i : 30, i : 50, and i : 100. Each pool is now sucked 

 into a Wright's pipette sealed at the end, and incubated at 37 C. 

 A control of emulsion without serum is also prepared and in- 

 cubated. The tubes are examined at the end of one hour, and 

 agglutination, if present, is most obvious. 



The diagnosis might also be made from a determination of the 

 opsonic index by the dilution method, or of the amount of immune 

 body, but these processes are much more tedious. 



Where a very early diagnosis is required (i.e., before the 

 appearance of the agglutination reaction) the bacilli may be 

 sought for in the stools or blood. This was formerly difficult, but 

 it has been greatly facilitated by the introduction of new methods 

 involving the use of special culture media, in which the bacilli 

 grow rapidly and form characteristic colonies. These are beyond 

 the scope of this work, and a description of them will be found in 

 Hewlett's " Bacteriology," second edition. 



Treatment. The curative treatment is not satisfactory. The 

 use of a simple bacteriolytic serum is useless or even dangerous, 

 for the reasons given earlier. The best hope for the future is 

 in the use of an anti-endotoxic serum, such as was prepared by 



