Dec. io, 1913 
Disease of Sugar-Beet and Nasturtium Leaves 
195 
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Fig. x,— Bacterium a ptatumirom. a 2-day 
beef-bouillon culture stained with 
carbol fuchsin. 
filaments (fig. 2, a and 6). In stained tissue of the hosts the average 
measurement of a single rod is 1.2 by o , 6 ft. The organism grown in a 
3-day-old beef bouillon culture and stained 
in carbol fuchsin has an average size of 2.1 
by 0.7/*. When stained with Toeffler's 
flagella stain, the average is 3.2 by 1.3/t. 
Process of Ceu, Division. —Cell divi¬ 
sion takes place in the bacterium by 
simple, transverse fission. In order to 
study the process of fission, agar hang¬ 
ing blocks containing the organism 
were made in the following manner: 
Thin beef-agar plates were poured and transfers from a bacterial 
culture streaked across the surface of the hardened agar. Agar blocks 
a few millimeters square were 
then cut out along the streak 
and transferred to clean cover 
slips. Care was taken to place 
the upper surface of the block 
next to the glass, after which 
the whole was turned over a 
Van Tieghem moist cell and 
kept at room temperature. At 
the end of 18 hours, by means 
of a microscopic examination of 
the agar block, with 2 mm. ob¬ 
jective (oil immersion) and No. 
6 ocular, bacteria were selected 
and their development through 
several generations was observed 
(%■ 3 ). 
Feageeea.— The organism is 
Fig. 2.— Filaments of Bacterium aptatum taken from 
the condensation water from a 2-day-old agar 
culture; stained with carbol fuchsin: o, Segmented; 
b, unsegmented. __ 
motile by means of polar flagella, varying from one to several at each 
pole. In general, the number is one to two, but occasionally three 
occur. The best results in staining flagella were 
obtained by the use of Toeffler’s stain, with acid 
mordant correction. Five drops of sulphuric acid 
(the acid of such dilution that i c. c. is neutralized 
by the same amount of i per cent sodium 
hydroxid) were added to 15 c. c. of mordant. The 
flagella are threadlike, frequently wavy and some¬ 
what tapering, often forming a loop or coil at the 
distal end, and are about twice as long as the body of the bacterium, 
actual measurement of 10 flagella giving an average of 4 ft (fig. 4). 
17072 °-13-2 
8 8 Hi I k 
abode T 
Fig. 3.—Process of cell division 
as seen in an x8-hour-old 
hanging drop culture of Bac¬ 
terium aptatum. Time, a to 
/, 5* minutes. 
