XOX-PATHOGEXIC BACILLI. 653 



a. 1.2 /* long and 0.8 to 0.9 H broad ; capsule not visible in hanging 1 drop. 



b. 1.6 to 1.8 Jt long and 0.8 to 0.9 ju thick; capsule clearly visible in 

 hanging drop ; usually in pairs ; both ends somewhat thickened as in a. 



c. Bacilli somewhat thicker than b ; capsule not visible. 



Friedlander's bacillus, 1 to 2 n long and 1 M thick. A second examina- 

 tion of all four, made at the end of forty-eight hours, showed no apparent 

 difference in a, b, and Friedlander's bacillus, while c remained shorter than 

 the others. None of the species retained their color when treated by Gram's 

 method. 



Biological Characters. Aerobic and facultative anaerobic, non-liquefy- 

 ing, non-motile bacilli. 



Upon gelatin plates 



a forms colonies resembling those of Bacillus coli communis; they spread 

 out in a thin layer, tbe margins of which are very thin and bluish by trans- 

 mitted light ; the contour is irregular ; later the colonies become thicker, 

 white, and opaque, and flap-like processes may be given off from the mar- 

 gins which double the original diameter of the colony of four to five mil- 

 limetres; in the centre a small, button-like elevation is seen. 



b. The colonies are at first thicker and more opaque than those of a ; 

 they reach a diameter of four millimeti'es, and are thinner toward the mar- 

 gin, which is irregular in outlhie; a small central prominence is usually 

 observed. 



c. The colonies are thicker, circular in outline, with smooth margins, and 

 attain a diameter of five millimetres ; the central projection is strikingly 

 large. 



In peptone-bouillon, at 36 C., at the end of five hours a, b, and c all 

 cause the culture medium to be decidedly clouded, while Friedlander's ba- 

 cillus only causes a slight cloudiness at the end of twenty-four hours. At 

 the end of a week the cultures of a show a dense clouding and an abun- 

 dant deposit at the bottom of the tube, but 110 layer on the surface ; the cul- 

 tures of b a similar cloudiness and deposit, and also a thick, gelatinous 

 layer on the surface ; the cultures of c a densely clouded medium with a 

 thin film upon the surface. Friedlander's bacillus, cultivated in the same 

 medium, showed a slight cloudiness and a few fragments of a mycoderma 

 floating upon the surface. In the cultures of b the whole fluid becomes 

 very viscid and can be drawn out into long threads ; the same character is 

 developed later and to a less extent in cultures of a ; and in c the superficial 

 film is somewhat viscid cultures of Friedlander's bacillus do not exhibit 

 this character. All of the cultures have an alkaline reaction, and those of 

 a, b, and c after a time have a disagreeable odor. 



In milk, at 37 C., at the end of a week coagulation is not complete, 

 although the fluid is very thick; b causes milk to be quite thick in two days, 

 and to be completely coagulated in four days; c, at the end of a few days, 

 causes the lower half of the milk to coagulate, and at the end of a week the 

 whole is firmly coagulated ; Friedlander's bacillus in milk did not produce 

 any apparent change. The milk cultures of a, b, and c had an acid reac- 

 tion ; at the end of two weeks some viscid serum was seen above the coagu- 

 lum in a, and the culture smelled like sour dough ; at the same time the 

 whole coagulum was viscid in the culture of b and a similar odor was per- 

 ceived ; the culture of c showed a superficial layer of serum which was not 

 viscid, and the odor was that of cheese. 



Upon potato a and b developed a thin, shining, grayish, transparent 

 layer ; the growth of c upon potato was thick and cream- white, resembling 

 that of Friedlander's bacillus. In cultures containing glucose, and in 

 mashed potato, c produced considerable quantities of gas equal parts of 

 COa and of H. Upon agar the growth of all is similar in appearance, but 

 that of a and b is very viscid, that of c less so, while Friedlander's bacillus 

 was destitute of this character. 



Smith concludes his description of these bacilli by the remark that they 

 may be identical with Bacillus lactis aerogeiies of Escherich. 



