22 INHIBITORY ACTION OF PARATYPHOID BACILLI 



1. The resulting fermentation takes the usual course as if no piior 

 inoculation had been made; i.e., the production of acid and gas goes 

 on quantitatively as in a fresh tube. 



2. The second organism multiplies actively, clouds the closed 

 branch as usual, but no gas is produced. Titration shows that the 

 usual amount of acid has been produced. 



In order to determine whether the particular type of second or 

 superadded fermentation is constant for the same organism, numerous 

 tests have been made during the past 1| years, with the result that 

 with the same combination of cultures the same result follows. 



Furthermore the various types of paratyphoid bacilli which hap- 

 pened to be on hand in the laboratory were tested to see just what 

 grouping would result if this kind of superadded fennentation were 

 used as a basis of classification. The results of this latter test are in 

 many respects suggestive. 



All true hog-cholera bacilli left the lactose medium uninfluenced. 

 The fermentation of the second organism proceeded as in a fresh 

 unused medium. Among the hog-cholera bacilli were those of widely 

 different ages. The oldest one had been isolated by one of us early 

 in 1886^ and was described at that time as a membrane-producing 

 variant. The most recent strain had been isolated by Dr. TenBroeck 

 at Camp Upton late in 1918 (No. XVI). 



Among cultures not isolated from swine. Bacillus icteroides Sana- 

 relli acted like a true hog-cholera bacillus. That this organism may 

 have been a true hog-cholera bacillus is made highly probable by the 

 experiments of Reed and Carroll.- They found a complete identity 

 of the two types in morphological, cultural, pathogenic, and agglu- 

 tinative characters. Bacillus icteroides also produced fatal enteritis 

 associated with necrosis of the mucosa of the large intestine in young 

 pigs. One of these experiments was so carefully controlled that the, 

 at that time, still unknown filterable virus of hog-cholera could hardly 

 have come into consideration as a cause of the lesions. Moreover 

 the autopsy notes do not suggest the filterable ^drus. 



^ Smith, T., 3rd Ann. Rep. Bureau Animal Industry, U. S. Depi. Agric, 1886, 

 622. 



2 Reed, W., and Carroll, J., /. Exp. Med., 1900-^1, v, 215. 



