86 BACTERIOLOGICAL DIAGNOSIS. 
The technique in either case is readily learnt and can 
be carried out with very little difficulty if the materials 
are at hand. But the test is one which is seldom advis- 
able for the home worker to attempt, as it requires a 
young culture of typhoid bacilli. We shall, however, 
describe the process, as some may carry it out during 
an epidemic, or if they are living where they have not 
access to a public laboratory. The process has now 
been greatly facilitated by the demonstration of the 
fact (by Widal) that the reaction is given with dead 
cultures of the bacilli. These cultures can be obtained 
from any bacteriological laboratory, and will keep. 
They are prepared by adding four or five cubic centi- 
metres of normal saline solution to an eighteen-hours- 
old culture of the typhoid bacillus on agar, scraping off 
the growth, filtering to remove clumps, and heating the 
emulsion to 60° C. for ten minutes to kill the bacilli. 
A small quantity of carbolic acid should be added to 
prevent putrefaction. With a supply of this culture on 
hand the practitioner can apply the test at home with- 
out much difficulty. 
Where the blood is to be transmitted to a laboratory 
it should be sent in a pipette specially made for the 
purpose. This consists of a bulb terminating in a 
capillary tube at one end and in a mouth-piece (which 
is plugged with cotton-wool) at the other (fig. 12, ¢). 
To procure the blood wash the patient’s skin and make 
a deep puncture with a sterilised needle; further anti- 
septic precautions are unnecessary. When a large drop 
of blood has collected upon the skin (and this may be 
hastened by gently squeezing the region, or by allowing 
the finger to hang down) the tip of the pipette is in- 
serted and suction applied. The practitioner must aim 
at filling the whole of the bulb with blood, and must 
