BACTERIA AND DISEASE 319 



crease and coalesce. In about ten days' time the culture 

 often turns a bright yellow, though it may remain white or 

 even take on a brown or olive tint. The entire mass of 

 growth is raised dry and crinkled, and composed almost 

 exclusively of threads. In its early stage small bacillary 

 forms occur, and in its later stage coccal forms. True clubs 

 never occur in pure cultures, although the threads may 

 occasionally show bulbous endings. 



Glanders in the horse and ass, and sometimes by com- 

 munication in man also, is caused by a short, non-motile, 

 aerobic bacillus, named, after the old Roman nomenclature 

 (malleus), Bacillus mallei. It was discovered in 1882 by 

 Loffler and Schiitz. It is found in the nasal discharge of 

 glandered animals. In appearance the bacillus is not unlike 

 B. tuberculosis, except that it is shorter and thicker. The 

 beading of the bacillus of glanders, like that in tubercle, 

 does not denote spores. B. mallei can be cultivated on the 

 usual media, especially on glycerine agar and potato. On 

 the latter medium it forms a very characteristic honey-like 

 growth, which later becomes reddish-brown. 



In the horse glanders particularly affects the nasal mucous 

 membrane, forming nodules which degenerate and emit an 

 offensive discharge. From the nose, or nasal septum, as a 

 centre, the disease spreads to surrounding parts. It may 

 also occur as nodules in and under the skin, when it is known 

 as " farcy." Persons attending a glandered animal may 

 contract the disease, often by direct inoculation. 



Mallein is a substance analogous to tuberculin, and is 

 made by growing a pure culture of Bacillus mallei in glycer- 

 ine-veal broth in flat flasks, with free access of calcined air. 

 After a month's growth the culture is sterilised, filtered, 

 concentrated, and mixed with an equal volume of a .5 per 

 cent, solution of carbolic. The dose is i cc., and it is used, 

 like tuberculin, for diagnostic purposes. If the suspected 

 animal reacts to the injection, it is suffering from glanders. 



