242 IMPORTANT VARIETIES OF FISSION-FUNGI. 



ing Typhoid loith Known Typhoid Bacteria. — The test con- 

 sists in the demonstration that the serum, properly col- 

 lected and diluted, ^ according to the instructions on pages 

 104 to 110, agglutinates typhoid bacteria from a twenty-four 

 hours' agar culture inside of an hour at 37°, when the 

 dilution is 50 times; or even, if possible, when diluted 

 100, 500, or 1000 times. 



Following exactl}^ the instructions on page 105, different 

 tests are made with varying strengths of serum and the 

 limit of the activity of the serum determined. If the 

 serum does not cause agglutination in dilutions higher 

 than 1 to 50, then no decision is possible, for serums 

 which are active when thus diluted occur without typhoid 

 fever being present or having previously occurred (25% 

 of healthy persons furnish serum which is active in dilu- 

 tion of 1 to 10). On the other hand, the absence of ag- 

 glutination does not absolutely prove that typhoid fever 

 does not exist, especially at the commencement of the dis- 

 ease, for before the third week the reaction is not so very 

 rarely absent; after the third week, it is lacking in only 

 1% of the cases (compare Bieberstein, Z. H. xxvii, 347). 

 The diagnosis of typhoid is most certain when, during the 

 course of the disease, the reaction having been previously 

 absent, it develops with increasing vigor (v. Leube). For 

 many details and the entire literature, consult Kasel (Ver- 

 handlungen der phys.-med. Gesellschaft in Wiirzburg, 

 xxxn, No. 6, 1899); in abstract, Kasel and Mann (Miinch. 

 med. Wochenschr., 1899, No. 18, 581). 



Not infrequently coli bacteria are influenced more 

 strongly than tj'^phoid bacteria by serum from typhoid 

 patients, and this is explained upon the entrance of coli 

 bacteria through the intestinal ulcers during the typhoid, 



^ The proposal to employ blood instead of serum in the diagnosis 

 of typhoid is often made and has been found practical. With a 

 pipet 0.1 c.c. of blood is placed in a small graduated cylinder and 

 diluted to 2 c.c. This blood mixture is tested and corresponds in its 

 effects to a serum diluted 40 times. Compare Babucke (C. B. xxili, 

 1092). If one possesses a Thoma-Zeiss counting apparatus for leuko- 

 cytes, 0.5 c.c. of blood maybe drawn into the melangeur and then 

 10 c.c. of water. Of the mixture, a drop is mixed with a drop of sus- 

 pension of bacteria. Thus the dilution becomes 1 to 40. (Eostoski, 

 Munch, med. Wochenschr. , 1899, 209. ) 



