388 INVESTIGATION, ETC., OF MILK-BORNE EPIDEMICS 



of this disease was, I felt sure, liable to mislead the clinical observer 

 in dealing with the early stages of a widespread prevalence of 

 disease accompanied by obscure feverish symptoms. 



" At the same time it became most essential in the public 

 interest to clear up, in as short a time as possible, any doubts as to 

 the actuality of a typhoid outbreak, so that the cause might be 

 ascertained and removed. Now the Widal reaction will give 

 results as early as the fourth or fifth day in cases of typhoid, and I 

 at once determined upon the wide application of this test. 



" The use of the Widal reaction in this outbreak is, I think, 

 deserving of some attention ; for, so far as I am aware, this is the 

 first occasion upon which it has been used on a large scale and has 

 proved successful, not only for confirming selected doubtful cases, 

 but in ' establishing ' a diagnosis amongst diverse cases with 

 feverish symptoms, where clinical observation was as yet at 

 fault. 



" My reliance upon the test seems to be fully justified by the 

 results, a summary of which I submit : — 



" In the case of 192 examinations made during the course of the 

 outbreak, between 19th October and 20th December, I have been 

 able to collate the Widal and clinical results ; I find (using a 

 dilution of in most cases i-io or 10-15, but in no case exceeding 

 1-20) that 121 gave a 'complete' reaction within an hour. 



" All these positive results were clinically confirmed with two 

 exceptions in which the clinical development of cases did not 

 support the diagnosis of typhoid ; so that, allowing these not to 

 have been typhoid, the error did not amount to 2 per cent. 



" In the case of 15 specimens examined, some definite clumping 

 was observed only after a period extending much over an hour and 

 considerable motility persisted. Of these doubtful cases six 

 developed as clinical typhoid, and nine proved not to be cases of 

 this disease. 



" In the case of 39 other specimens examined, negative results 

 were obtained, of which four developed clinical typhoid ; in two of 

 these latter an opportunity of a second examination was afforded and 

 gave then a positive result ; in the other two, a second examination 

 was not made. The other cases all proved to be not typhoid fever, 

 thus agreeing with the Widal reaction. I think I am justified in 

 considering these results satisfactory, especially as the examina- 

 tions were made under great pressure. 



" In a large number of cases the reaction I obtained was practi- 

 cally ' immediate,' complete clumping and entire loss of motility 

 taking place almost at once. 



" I use a hanging drop upon a cut-out moist blotting-paper cell, 

 and in the edge-region of the drop characteristic phenomena seem 

 to occur. 



" In these ' immediate ' reactions, the edge-track, which is the 

 scene of the busiest activity before the addition of the serum^ 



