SERUM DIAGNOSIS OF TYPHOID FEVER 389 



becomes quite deserted, and for some time the bacilli seem to have 

 disappeared from the entire field, until found in definite ' spellican ' 

 masses in various parts of the field. 



" Many other cases showed a reaction not quite so immediate, 

 but ' complete ' within five or ten minutes : in these I noticed often a 

 peculiar ' spinning ' motion of individual bacilli, to be seen fre- 

 quently in the tangle of a forming clump : the bacilli seeming as 

 if entangled by one or more flagella, and spinning rapidly round in 

 the effort to get free, this seems a somewhat definite indication of 

 typhoid clumping in progress, 



" The varieties of false clumping which occur do not seem 

 likely to cause confusion with a little practice ; but in certain cases 

 of scarlet fever upon which I tried the reaction, I observed in one 

 no reaction in half an hour, marked clumping in one hour and ten 

 minutes, but the clumps loosely aggregated, flat, and floating freely 

 in the fluid, the free bacilli still active ; after 2\ hours the masses 

 ' unclumped ' and in three hours the bacilli were quite dissociated, and 

 as active as in the original broth culture. 



" The observations during the epidemic were made, as I have 

 stated, with low dilutions, mostly i-io and never exceeding 1-20; 

 but I now examine a low dilution, i-io or I-I5,and a high dilution, 

 1-40 or 1-50; but if the low dilution gives a negative result, the 

 higher dilution is of course unnecessary. I find generally that, in 

 the blood from a case of actual typhoid, the reaction in the case of 

 the high dilution is very little less rapid and marked than in low 

 dilution. 



"The results obtained show, I imagine, that considerable 

 reliance can be placed upon the reaction when ' complete,' i.e. as to 

 aggregation and loss of motility, within a short time limit, even 

 when I-IO or 1-15 dilution alone is used. I do not think this time 

 should exceed an hour even for 1-50 dilution. 



" I used two cultures, one an agar subculture from one supplied 

 to me by Dr Klein ; the other an agar subculture from the spleen 

 of a fatal case during the outbreak ; broth cultures are made from 

 one or another of these daily ; they are both extremely active, 

 especially the older one ; for measurement, drop measurement on 

 a watch-glass seems sufficiently accurate, and is handier, especially 

 with small quantities of blood. I prefer blood collected in small 

 centre bulb-glasses : vaccine tubes are vexatious to blow out, and 

 apt to get over heated in the sealing — which accounts, I imagine, 

 for some of my negative results that proved wrong, as they occurred 

 under these conditions of collection. Zeiss D or an English ^-inch 

 objective appear the most convenient for observation. 



" Comparison of results. — Of the Widal examinations, 36 were 

 of cases admitted to the Royal Infirmary, Bristol. Of the ^6 cases, 

 26 gave a positive result : of these 14 acted almost immediately, 

 clumping and loss of motility being established in a few minutes ; 

 9 acted not quite so rapidly, the reaction being complete within 



