TYPHOID FEVER. 483 



From these animals serums were secured not exactly an- 

 titoxic, but anti-infectious or auti-microbic in operation, 

 and possessed of marked specific germicidal action upon 

 the typhoid bacilli when simultaneously introduced into 

 the peritoneal cavity of guinea-pigs. 



The action of the typhoid serum is specific, and exerts 

 exactly the same action upon the typhoid bacilli as the 

 cholera serum exerts upon the cholera spirilla, killing 

 and dissolving them (Pfeiffer's phenomenon). 



So far, no serum has been produced that is efficacious 

 in human medicine. 



The specific reactions of the serums artificially pre- 

 pared can be used to differentiate cultures of the colon 

 and typhoid bacilli, the typhoid bacilli alone exhibiting 

 the specific effect of the typhoid serum. 



Richardson ' has found it very convenient to keep on 

 hand in the laboratory filter-paper saturated with typhoid 

 serum and dried, then cut into }4 c.cm. squares. To 

 make a differential test of the typhoid bacillus one of 

 these little squares is dropped in ]/ 2 c.cm. of a 24-hour- 

 old bouillon culture of the suspected bacillus and al- 

 lowed to stand for five minutes. Then a drop of the 

 fluid placed upon a slide and covered with a cover- 

 glass will show typical agglutinations if the culture 

 be one of typhoid-fever bacilli. In a second mention 

 of this method 2 he has found its use satisfactory in 

 practice and the paper serviceable after fourteen months' 

 keeping. 



Christophers 3 found that the serum from typhoid 

 patients occasionally caused agglutinations in cultures 

 of the colon bacillus, but concludes that this does not 

 lessen the specificity of the reaction, as there may be 

 two combined specific actions of these serums. Experi- 

 ments on rabbits established that typhoid and colon 

 serums could be produced, each specific in its agglutin- 



1 Centralbl f. liakt. u. Parasitenk., 1897, p. 445. 



1 Journal 0/ Experimental Medicine, May, 1898, p 353, note. 



3 Brit. Med. Jour., Jan. 8, 1898. 



