240 BACTERIOLOGY OF THE EYE 



A further case has been observed in my clinic by Kayser. Macnab 

 records a case of keratomalacia in the secretion from which a 

 mixture of coli, Pneumococci, and a Gram-negative Diplococcus were 

 found. 



The organisms in the secretion: A point of differential diagnosis 

 is brought out in the drawing on Plate I., where the Gram-negative 

 bacilli are seen to vary in length. Occasionally they present the 

 appearance of Diplolacilli, but not nearly so constantly as does the 

 Morax-Axenfeld bacillus ; on the other hand, long threads can be seen 

 as well as single, short individuals. When examined carefully they 

 cannot be confused with Diplobacilli. The resemblance to Zur 

 Nedden's bacilli is closer (Plate III., Fig. III.), though these latter 

 are slightly curved, and are somewhat smaller. 



Shortly stated, its characteristics are as follows : 



Short rods with rounded ends, not forming spores, without capsules, about 

 0'7 to 0'8 fjL broad, 1 to 3 //. long, in singles or pairs, rarely longer ; the smallest rods 

 look like cocci. 



Gram staining is negative ; motile. The activity of movement is not very great 

 (in contrast to the Bacillus typhO8U8), corresponding to the fact that there is only 

 one flagellum at the end of the bacillus. The motility is very often rapidly lost in 

 cultures as the flagellse are cast off, and appear free in the fluid of the stained 

 preparation, swollen, rolled up, or tangled. In the case of bacilli which appear to 

 belong to the coli group, but do not show any motility, we must therefore examine 

 very young cultures in the hanging-drop, and with the special stains for flagellae 

 (cf. ' Technical Remarks,' p. 15). In a case of coli blennorrhcea published by Bietti 

 we were only able to find definite motility in cultures which were not more than 

 ten to twelve hours old. 



It is a facultative aerobe. Growth takes place on all media, even at room 

 temperature. The greyish-white iridescent colonies spread out on gelatine as a 

 circular or dentate film, growing rapidly even at room temperature (typliosus 

 grows slowly). The gelatine is not liquefied. On agar a greyish-white, glistening, 

 transparent scum. In bouillon a diffuse clouding, usually with the formation of a 

 thin scum ; development of acidity, which in the older cultures again disappears. 

 With varying rapidity milk is coagulated with acid formation. In grape-sugar 

 bouillon acid formation occurs with gas development, especially of oxygen and 

 carbonic acid. In sugar agar and sugar gelatine there is a definite development of 

 gas bubbles. On alkaline potatoes there is a thin yellowish scum. On the addition 

 of nitrite of potash and sulphuric acid to a twenty-four-hour bouillon culture 

 there is a red colour the nitroso-indol reaction. The intensity of this reaction 

 varies with the particular medium. Gunther, therefore, recommends that a control 

 with a standard coli should be used. 



Of the cases which have been published in the German literature, those of 

 Axenfeld, Taylor, Bietti, Mircoli, Mercanti, Mazet, Uhthoff, Ricchi, Randolph, 

 de Berardinis, Jarnatowski, and Zur Nedden, have all shown the well-known charac- 

 teristics of the Bacterium coli to a varying extent. Groenouw's results differ, in 

 that he did not find gas formation or the indol reaction. The bacilli of Vossius 

 and Markwald were not quite typical. Opinions will vary as to whether these 

 variations should still be reckoned as the Bacterium coli. 



