DIAGNOSIS 



ever, that in the largest number of cases no such explanation can 

 be found. As regards a clinical differentiation of the three varieties 

 of enteric — typhoid, para B, para A — this is impossible, at least in 



a).rO,i. P6 ,7 .0 .D so 21 }l 



21 21 25 26 27 26 29 3 



0 31 32 13 34 35 36 



















wm 



Fig. 661. — Temperature Chart of a Triple Infection of Typhoid, 

 Paratyphoid A and B Fevers. 



the tropics. With these clinical difficulties the bacteriological 

 diagnosis of enteric fever acquires in the tropics even more import- 

 ance than in temperate climates. 



The bacteriological diagnosis of enteric is based on the following 

 methods: — 



1. Agglutination test. 



2. Haemocultures. 



3. Search for the enteric bacilli (B. typhosus, B. paratyphosus A, 

 B. paratyphosus B) in stools and urine. 



4. Splenic puncture. 



5. Ophthalmo-reaction and cuti-reaction. 



6. Subcutaneous inoculations of dead cultures and Vincent's 

 splenic diagnosis. 



7. Complement fixation, etc. 



The first two processes are really the only ones of practical im- 

 portance, but a few words may be said also on some of the others. 



Agglutination Test (Widal Reaction).— This test is based on 

 the work of Griiber, Durham, Widal, and Griinbaum. Either the 

 microscopical or the macroscopic method may be used. The simplest 

 way to perform the microscopical test is to place on a slide 19 loop- 

 fuls of broth and i of blood, and mix the whole gently together. 

 A loopful of this dilution is then mixed with a loopful of a young 

 typhoid broth culture, a hanging-drop made, and the preparation 

 examined microscopically for agglutination after one hour. The 

 technical details may be found in any textbook on bacteriology. 

 It suffices here to say that the blood should be sufficiently diluted— 

 at least i in 40 — and the agglutination should be first tried, using 

 the typhoid bacillus, and if this is negative, the paratyphoid A and 

 the paratyphoid B bacilli. If the medical man in attendance 

 cannot perform th^e test himself, he should send the blood to a 

 bacteriological institute. The sample of blood is obtained by prick- 

 ing the finger and collecting a few drops of blood in a capillary tube. 

 After closing both ends in the flame, the tube is packed in cotton- 

 wool, and despatched to the bacteriological institute. 



