BLOOD AND THE IDENTIFICATION, ETC. 617 



In 1895, Washbourn saw similar appearances, and 

 remarked that the mode of growth in the serum seemed to 

 give a good indication of its protective power (13). 



All these observers appear to have worked with un- 

 diluted serum only, and that too acting for a considerable 

 time. Although they examined the deposit with the 

 microscope they do not appear to have investigated 

 microscopically or otherwise, either the immediate effect 

 of the serum on the bacilli, or the effect of diluting the 

 serum. 



In 1894 R. Pfeiffer published what is now known as 

 Pfeiffer's reaction (11), but it was Bordel who, in 1895, 

 trying to simplify Pfeiffer's reaction, first described any 

 observations in which the above-mentioned neglected 

 aspects of the question were considered. He saw the 

 agglomeration and loss of movement, but failed to attribute 

 any specific importance to the reaction {2a). 



It was therefore left to Durham and Gruber, who had 

 already been more than six weeks at work on the subject 

 when Bordet's investigations were published, to show how 

 valuable and characteristic this reaction could be made, 

 and to establish its general applicability {/\.a, 6a). 



In March, 1896, I applied the reaction to the diagnosis 

 of enteric fever in man, but scarcity of material and other 

 delays prevented any paper on the subject appearing before 

 September [ya). Meanwhile Widal, profiting by a hint 

 thrown out by Professor Gruber at the Wiesbaden Congress 

 {6c) in April, and having more cases at his disposal, was 

 able to publish a communication on serum-diagnosis early 

 in July ^ (14c?). Pfeiffer's reaction is observed by injecting 



1 Professor Widal has persistently ignored the dates given in my articles 

 and constantly represents me as having merely confirmed his results. As 

 a matter of fact, so far as I am concerned, the invention of serum diagnosis 

 was made independently, possibly earlier, and arrived at from an opposite 

 point of view. On the other hand, there are certain points, e.g., (i.) action 

 of serum from other than enterica patients, (ii.) action of human serum on 

 bacilli other than B. typhosus, (iii.) variability of strength of serum in enterica 

 patients from day to day, (iv.) difference of sera of mother and child, and 

 (v.) desirability of accurate dilution, contained in my papers ; these Professor 

 Widal has incorporated and repeated without acknowledging their origin. 



