470 



INFECTIVE DISEASES. 



FIG. 193. SPORES OF BACILLUS 

 ALVEI. 



Cheyne investigated foul-brood, isolated the bacillus, and fully 



described its morphological and biological characters in nutrient 



media. By removing the cap of 

 one of the diseased cells, the de- 

 composing larva can be withdrawn, 

 and cover-glass preparations will 

 reveal delicate bacilli and large oval 

 spores. The bacilli can be readily 

 isolated and cultivated in nutrient 

 gelatine. 



Bacillus alvei (Cheshire and 

 Cheyne). Hods varying in size, 

 and forming large oval spores. 

 They are motile and possess flagella. 

 Cultivated in nutrient gelatine in 



test-tubes, a delicate ramifying growth appears on the surface, 



and irregular whitish masses arise along the needle track. Pro- 

 cesses shoot out from these masses, and 



extend through the gelatine for long 



distances. They are thickened at points 



in their course, and are clubbed at the 



ends. The gelatine is gradually liquefied, 



and the bacilli form a loose, white, floccu- 



lent deposit at the bottom of the tube. 



The liquid in the tube becomes yellowish 



in colour after a time, and gives off an 



odour of stale, but not ammoniacal, urine. 



On the surface of nutrient gelatine the 



bacilli grow out in chains of rods in single 



file, or of rows of several side by side. 



The processes which are formed tend to 



curve, and at a short distance from the 



track of the needle form a distinct circle, 



from which another process grows out, 



and a fresh circle is developed. The 



gelatine in the vicinity of the bacilli 



gradually liquefies, and channels are 



formed in the gelatine in which the 



bacilli move backwards and forwards. 



On nutrient agar-agar a whitish layer 



develops, consisting of bacilli arranged side by side, which in a 



few days are replaced by rows of spores similarly arranged. 



FIG 194. PURE-CULTURE IN 

 NUTRIENT GELATINE, x 4 

 (CHESHIRE AND CHEYNE). 



On 



