STUDIES UPON AGGLUTINATION IN THE COLON- 

 TYPHOID GROUP OF BACILLI 



O. ISHII 



From the Deparlmertl of Preventive Medicine and Hygiene, Harvard Medical School, 



Boston, Massachusetts . 



Received for publication April 19, 1921 



THE PREVENTIVE ACTION OF FORMALIN IN THE AGGLUTINATION 



TEST 



Malvoz in 1897 claimed that formalin produced chemical 

 agglutination of Bod. typhosum, but not of Bad. pnratyphosum 

 and Bad. coli, while, on the other hand Beco, Kemy, Widal and 

 Nobecourt were unable to confirm Malvoz's observations. 



By adding amounts of formalin from 0.05 to .5 per cent to 

 broth or agar cultures, I have obtained no e\adences of chemical 

 agglutination with Bad. paratyphosum A and B, Bad. dysen- 

 teriae and Bad. coli; with concentrations of 0.0.5 to 0.3 per 

 cent formalin spontaneous agglutination in these cultures was 

 almost or entirely prevented while Bad. typhosum and Bad. 

 paratyphosiim A showed spontaneous agglutination without for- 

 malin but none with it, when the above dilutions were used. 

 WTien concentrations of 1 to 5 per cent were used slight spon- 

 taneous agglutination sometimes occurred. Spontaneous agglu- 

 tination was more or less inhibited in all dilutions with Bad. 

 paratyphosum B. With Bad. coli there was absolutely no change 

 in spontaneous agglutination when formalin was added. 



From the above facts it is evident that a concentration of 

 0.05 to 0.2 per cent formalin gives the most satisfactory results 

 in the prevention of spontaneous agglutination, correct read- 

 ing being possible at the end of two hours. However, it is a 

 better rule to let the tubes stand over night. 



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