A NEW PATHOGENIC BACILLUS 
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It is to be noted that in dilution i : 50, B. enteritidis was clumped by the sera 
from the two known cases of typhoid.* Bacillus ' L ' was also clumped, although to 
a less extent, by one of the typhoid sera. The interaction of these allied bacilli and 
their sera was more fully studied by the use of immunized animals ; reference to 
these studies will be made later. 
Comparative Bacteriological Study of Bacillus ' L ' 
Inoculations were made upon all media with the following organisms : — 
A. B. typhosus group. 
1. B. typhosus (A.D.) ; turns milk alkaline after a week. 
2. B. typhosus (L.C.) ; milk remains acid after many weeks. 
3. B. typhosus (B.T.A.) ; milk remains acid after many weeks. 
B. B. enteritidis group. 
1. B. enteritidis (Gartner). 
2. B. paracolon (Le Sage). 
C. B. coli group. 
1. B. coli (Escherich) ; does not ferment saccharose. 
2. B. coli ('Communior ' |) ; ferments saccharose. 
The results were compared with simultaneous inoculations of two cultures of Bacillus 
' L,' one isolated from the faeces, the other from the urine of the patient. With 
minor variations, the results of the inoculations were so constant within each of the 
above groups — A, B, and C — that for the sake of conciseness, Bacillus '1/ will be 
compared with the three groups as units rather than with individual bacilli. (See 
Table V as appended.) 
Notes on the Methods of Study 
Morphology. The only observed difference between Bacillus ' L' and B. typhosus 
lay in the regularly observed polar staining of the former. This was best seen when 
young agar cultures were lightly stained with Carbol fuchsin ; it was not so well 
brought out by Methylene blue, but was clearly made out by the use of Zettnow's 44 
silver method. 
Flagella. The method of staining found most satisfactory was the one devised 
by Dr. Zettnow 44 ; the mordant consisting of antimony tartrate and tannic acid; the 
stain, of a solution of silver sulphate in ethyl-amine (30 per cent.). 
Potato. As has been often pointed out, this method of differentiation is very 
unreliable. Cushing 5 shows that all depends upon the initial reaction of the potato. 
* This confirms the opinion expressed by Durham (8), i.e., that in dilutions below i : 100, B. enteritidis may often 
react as well as B. typhosus with known typhoid sera. To account for this reaction he has since then formulated a theory (9) 
which certainly helps to explain one of the intricate phenomena of agglutination. 
■f The expression B. coli 'communior' is borrowed from Durham (9). 
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