THE BIOLOGICAL CHARACTERS, ETC. 31 



five kinds of bacilli from the Merrimac which exhibited a 

 growth on this medium exactly of the same character as that 

 of the typhoid bacillus. Dunbar (17) considers that culture 

 methods generally only complicate the solution of the problem 

 of differential diagnosis of E berth's bacillus from the bac- 

 terium coli commune, and the attempts made in this direction 

 by Uffelmann {37), Vincent (41), Gasser (42), Holz (39), 

 Parietti (40), Chantemesse and Widal, Laruelle (38) and 

 Wurtz (35), which are all culture methods, are, according to 

 this observer, insufficient. Quite recently Inghilleri (43) 

 regards the growth of these bacteria upon amygdalin-bouillon 

 as differential. Bacillus typhosus does not as in the case with 

 the colon bacterium act like emulsin and decompose the 

 glucoside with production of hydrocyanic acid. This effect 

 however is certainly accomplished by other micro-organisms, 

 as Telmi and Montesano have shown ; the blood of cholera 

 patients and the dejecta of those suffering from typhoid fever 

 also possess the same property. 



Recent papers have again brought into prominence the 

 possibility of establishing a diagnosis between the above 

 bacteria by culture methods. Buchner (18) first pointed out 

 the anti-bacterial action of formalin, though a note on 

 this fluid had been given by Low (19). This agent has 

 been employed by Schill (20) in order to obtain a differential 

 culture medium. He describes a water bacterium which 

 occurs with Escherich's bacterium in spring and canal water. 

 This resembles bacillus typhosus since it does not coagulate 

 milk, but resembles bacterium coli commune since it develops 

 gas in sterile bouillon and grows on potato with the produc- 

 tion of a well-marked, yellowish green crop. To determine 

 the nature of this water bacterium comparative experiments 

 were made to differentiate bacillus typhosus from bacterium 

 coli commune. A formalin-bouillon 1 : 7000 is prepared, 

 and this is inoculated. When working with dejecta it is 

 found that if the bouillon clouds this effect is due to the 

 presence of Escherich's bacterium and is a valuable diagnostic 

 character since bacillus typhosus causes absolutely no tur- 

 bidity. This fact does not, however, definitely establish the 

 presence of this microbe, since probably other water bacteria 



