BACTERIOLOGY OF SOME DISEASES OF SHEEP 5 



where it was moved gently to and fro for 10-15 seconds. It was now finally 

 transferred to 2 7^ silver nitrate, and left until the silver bath began 

 to turn brown, when it was removed and again washed in distilled water. 

 To ensure a sufficiently deep staining, it was mounted in water and 

 examined under an oil immersion lens. If the staining was not 

 sufficiently deep, the latter process of washing in sodium acetate solution 

 and silver nitrate was repeated. By this process, very distinctive staining 

 of the cilia was obtained. 



The cilia varied in number from i to 10, averaging five; all were of 

 equal diameter, but varied in length from lO/x to 20/>i. They took their 

 origin from any part of the periphery of the bacillus, from which they 

 pursued a waving tortuous course. Sporing forms of the rods also 

 possessed cilia, a fact which was in accordance with the slight movement 

 which these also showed. As stained by Loeffler's method the cilia 

 were hardly recognisable even with a magnification of 960 diameters 

 on account of their extreme delicacy. 



Growth on Gelatine. 



In stab cultures under oil, growth was apparent in from 3-10 days — 

 the longer the time the bacillus had been under cultivation the quicker 

 the growth. In many cases the gelatine tubes were inoculated by means 

 of a capillary pipette, and its track was shown by a liquefied cone of 

 the medium demarcated from the solid part by numerous small, 

 pin-point masses of a greyish-white colour. From the surface of the 

 cone, horizontal, thread-like processes pursued a tortuous course to the 

 periphery of the tube. At first, these processes were short and fluffy, 

 and better seen at certain points of the cone. After further incubation, 

 they increased in length and number. They might become so numerous 

 that, matted together, they almost occluded the central cone. Here and 

 there, throughout the growth, small, pin-point, fluffy dots were seen. 

 Occasionally some of these processes behaved like the first inoculation, 

 and repeated the original picture on a very small scale. The picture of 

 a growth from a bacillus which had been cultivated in the laboratory for 

 some time was not so complex. The liquefied cone sometimes contained 

 no deposit, and the hair-like processes, although numerous, long and 

 wavy, were still discrete. After longer incubation, the threads dissolved, 



(405) 



