NOTE ON THE SPECIFIC ACTION OF NORMAL 
HUMAN SERUM UPON THE BACILLUS 
COLI COMMUNIS* 
By S. R. CHRISTOPHERS, M.B. Vict. 
From the Pathologicai, Laboratory, University College Liverpool 
The application of the serum diagnosis to the differentiation of the typhoid bacillus from 
the various varieties of the bacillus coli communis has not hitherto been as satisfactory in its results 
as might have been anticipated. 
PECKHAMt gives a table showing the action of typhoid human serum upon 70 cultures 
ot typhoid and coli bacilli obtained from various sources, and lays stress upon the anomalous 
results obtained by her application of this test to the differentiation of the two forms. In lier list 
the majority of cultures giving the biological characters of coli were undoubtedly agglutinated b)- 
human typhoid serum ; one in particular she mentions as giving the reaction as fully, that is, 
clumping, and almost entire cessation of movement, as did any of the typhoid cultures. 
ZiemkeJ states that whilst using cultures of coli as controls in the performance of 
the Widal test, he frequently found that they were agglutinated by typhoid human serum. 
Bensaude§ also states that tiie agglutinins of typlioid serum act upon the B. coli, tliough 
in a less degree than upon the typhoid bacillus, and explains this action as being due to the close 
biological relationship of the two organisms. 
Such marked action of typhoid serum upon the B. coli would naturally invalidate the strict 
specific nature of the reaction between typhoid serum and the typhoid bacilli. There is, however, 
a source of error, which I have not seen mentioned, which may be to a large extent responsible for 
these puzzling results. It is that many have used, as the differentiating test, the blood of hmnan 
typhoids. Now, in the following table, it will be seen that normal human serum has, in the great 
majority of cases, as specific an action upon the bacillus coli communis as has the serum of a 
typhoid patient upon the bacillus typhosus ; that, in fact, the serum of a typhoid patient probably 
has two distinct specific actions, one upon the tvphoid bacillus due to infection by that organism, 
and one upon the B. coli, an action which is present alike in typhoid and non-typhoid sera. 
Table I shows the action of a number or non-typhoid and typhoid sera upon the B. coli, 
with the amount of dilution with which the reaction could be obtained. The coli organism used 
* Reprinted from the 'British Medical Journal.' J Ziemke. 'Deutsche Med. Wochensch,' 8 April, 1897. 
■f The 'Journal of Experimental Medicine,' vol. ii. No. 5, § ' Le phenomene de I'agghitination des Microbes,' par 
1897. Raoul Bensaiide. 
* H 
