Widal Reaction of Agglutination 509 



of 1 : 10 or 1 : 15, etc. Twenty-four hours afterward the cloudiness 

 characteristic of the growth of the typhoid bacillus in bouillon had 

 entirely disappeared, because the bacilli, massed together, had all 

 sedimented, and were found as a flocculent sediment at the bottom 

 of the tube. This he called the "rapid method," in contradistinction 

 to a more rarely employed "slow or culture method," in which the 

 serum in the given proportion was added to the sterile bouillon, which 

 was inoculated with the typhoid bacillus and stood in an incubating 

 oven for about fifteen hours, or until the growth could be observed 

 in a flocculent mass at the bottom of the tube. Pugliesi * used serum 

 obtained from blisters for the same purpose. 



Both these methods were so annoying to the patient that, had 

 no improvement in the technic been devised, it is probable that the 

 reaction would have attained little importance as a method of diagnosis. 

 Widal himself made the first improvement, and suggested that instead 

 of a syringeful of blood a few drops be secured from the finger-tip. He 

 also recommended observing the reaction through the microscope 

 instead of awaiting the results of the slow sedimentation that succeeds 

 the addition of the blood to a culture, and found that it was un- 

 necessary to use fresh serum, as serum that had been kept for some 

 time produced all the phenomena in a typical manner. 



Wyatt Johnston, f independently of Widal, found that successful 

 reactions could be obtained from blood dried upon paper and redis- 

 solved in water. The practical use of his observation was made by 

 having all specimens of blood to be tested by the Widal method dried 

 upon paper and sent to the laboratory at Montreal, where they could 

 be studied and reported upon. A ready and certain means of diagnosis 

 of doubtful cases of typhoid fever having been long desired, this method 

 met with ready acceptance. Indeed, the outcome of Johnston's work 

 was the establishment, at the laboratory of the Board of Health of the 

 Province of Quebec, and later at most public laboratories in this country, 

 of a system of free examinations of typhoid bloods, by which the 

 physicians of the larger cities and towns can have their diagnoses 

 confirmed. 



The paper upon which the blood is dried is moistened with germ- 

 free water, and a drop of the solution placed upon a cover-glass that 

 has just been passed through a flame. A drop of a bouillon culture, 

 or of a watery suspension of an agar-agar culture of the typhoid bacillus, 

 is mixed with it, the cover placed upon a concave slide to make a 

 "hanging drop" (q. i;.), and is then examined under a dry lens of 

 moderate power (one-fourth or one-fifth inch). This was Johnston's 

 technic. Wesbrook endeavored to improve it by having the blood 

 sent to the laboratory dried upon carefully weighed pieces of tin-foil, 

 prepared for the purpose in the laboratory. The advantage of this 

 is that the exact weight of the dried blood can be determined, and 

 accurate dilutions made. 



Cabot has made use of the medicine dropper: he secures blood from 

 the finger and drops it into a receptacle, afterward adding a given 

 number of drops of bouillon culture from the same medicine dropper. 



Robin J has improved upon this method by using a Hoffman clamp 

 by which the bulb of the medicine dropper can be more accurately 

 compressed than with the fingers. The blood is drawn into the dropper 

 and then, by gently screwing up the clamp, a drop is allowed to fall 



*"Riforma Medica," Oct., 1896. 

 f "Montreal Med. Jour.," 1897. 



J Bull. No. 5 (Sept., 1900) of the Bact. and Path. Lab. of the Dela- 

 ware State Board of Health. 



