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, c). 

 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 



