112 
Journal of Agricultural Research 
Vol. VIII, No. 3 
as little as possible and to introduce the inoculating loop only into the 
upper layers of the culture liquid. 
In 18 hours there was no growth in any except B . phytophthorus from 
Schuster which showed a little clouding in the upper layers. Daily 
observations were made following this for several days. 
In 36 to 48 hours as compared with normal broth cultures inoculated 
at the same time those of B. atrosepticus , B. solanisaprus , B. melanogenes , 
IIIA, SE, and IIP were much restrained, but there was an evident slight 
clouding all through, slightly stronger at the top. The same condition 
prevailed as long as the cultures were under observation, except that 
after three or four days the three organisms from Maine showed a more 
vigorous growth than the other three and produced a distinct, moderate 
clouding all through the bouillon. The appearance of the first three 
named was identical in all respects. 
The growth in the cultures known as B . phytophthorus from Appel and 
from Schuster after about 48 hours was unrestrained and appeared 
equally as abundant as that in the check tubes. 
Best media for long-continued growth. —Of the various media 
used, neutral beef bouillon, made either from meat infusion or from 
Liebig's extract, proved to be the best for long-continued growth. 
PHYSICAL AND BIOCHEMICAL FEATURES 
Fermentation of carbohydrates. —The ability of the different 
organisms in this group to ferment various carbohydrates has furnished 
perhaps the most important differential characters upon which the pre¬ 
viously named species have been erected. Therefore in the present 
studies more attention has been given to this subject than to any other. 
The results obtained are not based upon single trials, but upon repeated 
tests of each organism. All the fermentation tests were made in uni¬ 
form fermentation tubes, having a small neck, a large bulb, and a 
capacity of about 25 c. c. in the closed arm. These were made to order 
and very closely conform to the illustration given by Smith (32, v. 1, 
p. 53). Both meat-infusion bouillon, previously freed from muscle sugar 
by inoculation with B . coli , and meat-extract bouillon made from Lie¬ 
big’s extract and tested for the absence of fermentable carbohydrates, 
as previously described, were used. The meat-extract bouillon was used 
for a large proportion of the work, for it was found to be more satisfac¬ 
tory. For the fermentation work 1 per cent of the carbohydrate used 
was added to the culture medium and the tubes containing the media 
were sterilized by fractional steaming. The following substances were 
tested for fermentation in this way: Dextrose, saccharose, lactose, mal¬ 
tose, glycerin, mannit, and dextrin. In addition some of the organisms 
were tested in the neutral-red lactose broth which is commonly used in 
water work as one of the presumptive tests for B . coli. The culture 
medium in each case was made neutral to phenolphthalein. 
