" BRAXY " SHEEP DISEASE IN AUSTRALIA. 573 



difficulty, if not impossibility, of isolating the bacillus by other 

 means, but as experiment has shown that on account of its rapid 

 loss of virulence when grown in artificial media, especiall- glucose 

 media, it is the only method which is likely to render satisfactory 

 results. 1 



Characters of the Bacillus. — Rod-shaped bacteria, single and in 

 pairs (which often look like single bacilli). Size \'aries from 2 to 4 

 microns in length, but occasionally rods twice this length may be 

 observed in the effusions, and in cultures ; breadth varies from 0.8 

 to 1.0 microns. Frequently the pairing bacilli, especially in the 

 wet preparations, are seen to form an obtuse angle. Motility is very 

 feeble ; with the Tasmanian bacillus I have always failed to satisfy 

 myself that there was any progression of the bacilli either in oede- 

 matous fluids or in cultures, however freshly examined, at most a 

 rolling motion being occasionally detected, whereas with the 

 Victorian bacillus a definite but generally feeble motility can readily 

 be observed : Gram positive if stain carefully applied : forms spores 

 readily in tissues and body fluids and also in media, such as serum 

 broth, but few are formed in glucose media : strict anaerobe, al- 

 though in common with other so-called anaerobic bacilli may be 

 grown, as will be seen later, under what are generally considered 

 aerobic conditions : produces gas in all media, with more or less 

 definite odour varying from a cheesy to a urinary odour, according 

 to circumstances of growth. 



Cultures in Liquid Media. — In ordinary broth, neutral or even 

 slightly alkaline to litmus, no growth occurs even under the strictest 

 anaerobic conditions ; the addition, however, of one-fifth to one-third 

 of ordinary sterile serum of any origin {i.e., cow, horse or sheep) 

 enables a rapid growth and copious growth to be secured. 



In glucose media (-}- 0.4 to -f 1 to phenolphthalein) if freshly 

 prepared and under anaerobic conditions, the growth is rapid, and 

 may be rendered more copious by the addition of 10 % to 15 % 

 of alkaline serum, non-coagulable by heat. In such fluid media 

 containing glucose the reaction rapidly becomes definitely acid, 

 and the bacilli soon fall to the bottom of the tube, forming a deposit. 

 In media without glucose the reaction remains neutral to litmus. 



Special Method. — -The simplest method of securing cultures 

 after the organism has been procured in a pure state con- 

 sists in employing a small portion of the affected muscle from an 

 experimental sheep, which muscle has been cut into strips and dried 

 at about 55° C. In such dried muscle the virulence may be retained 

 indefinitely — at least after 18 months I find no diminution. If a 

 small portion, about one to ten centigrammes, of such dry muscle 

 be placed in a test tube containing ordinary broth, neutral to litmus, 

 and boiled for thirty seconds in order to destroy any organisms 

 which may have settled on the surface during drying, and rapidly 

 cooled, after six to ten hours at 37° C. growth is manifested by a 



fl. See Veterinary Journal, Vol. LXVI., No. 419, p. 254 (May, 1910), and Appendix B. II.] 



