72 CLINICAL BACTERIOI,OGY AND HyEMATOLOGY 



Sterile test-tube, and heating to 60° C. for half an-hour to ensure 

 sterility : 



Normal saline solution (o'8 per cent.) 450 c.c. 



Carbolic acid (liquefied) i"25 c.c. 



Glycerin - 50 c.c. 



Boil and allow to cool immediately before use.* 



The bacilli gradually separate from an emulsion prepared in 

 this way, but are distributed throughout the fluid by shaking. 

 With a supply of this culture at hand the practitioner can apply 

 the test at home without difficulty. 



Collect the blood from the ear, as described on p. 34, taking 

 care to get a Wright's pipette about half full. The test may be 

 applied to a dry drop of blood, but in this case there is no 

 possibility of making an accurate dilution, and unless a fair 

 quantity of serum is at hand it is impossible to perform the test 

 by the macroscopic method. 



If a pipette is not at hand, it is easy to manufacture one out 

 of any piece of glass tubing which may be available. 



Method of performing Widal's Reaction by the 

 Microscopic Method. 



Requisites. — i. A young culture (not more than eighteen hours 

 old) of typhoid bacilli on agar. 



Where dead bacilli are to be used, this is to be replaced by a 

 culture obtained from the laboratory and prepared in the manner 

 described. 



2. A small funnel provided with a double thickness of white 

 filter-paper. This is unnecessary if dead cultures are to be used. 



3. Three clean watch-glasses. 



4. A platinum loop. This should be made of fine wire and 

 have a loop (which must be completely closed) about -j^j- inch in 

 diameter. 



5. A hollow-ground slide. This is an ordinary slide having a 

 well about ^ inch in diameter sunk in its centre. If it is 

 not at hand a cell may be built up on an ordinary slide. Take a 

 piece of thin card i inch square and cut out a square A inch in 

 diameter from its centre. Fix this perforated square down on to 

 the slide with vaseline or immersion oil. 



* J. H. Borden, Proc. N. Y. Path. Soc. , 1904. 



