1909.] Disease of Bees in the Isle of Wight. 819 



stained so as to demonstrate bacteria, were examined. Bacteria were 

 far more numerous in the diseased specimens, and the plague-like 

 organisms were frequently observed in them. In the least marked 

 cases they were mainly confined to a layer of poorly staining material, 

 which is constantly found in contact with the internal aspect of the 

 lining membrane. In some places they were found between the cells 

 passing down almost to the basement membrane. In the more advanced 

 cases they were found in large numbers in the granular material filling 

 the lumen of the gut, and between the cells of the desquamated 

 epithelium. Great numbers were found near to the basement 

 membrane in those regions in which the cells had become detached. 

 Frequently they seemed to be within the degenerated cells. 



Characters of the Plague-like Bacillus. — In film preparations made 

 from small portions of the chyle stomachs of diseased bees teased out 

 on glass slides and stained with methylene blue, the bacillus appears 

 as a short, round ended, thick organism with darkly staining ends and 

 lightly staining central bands (polar staining), and closely resembles 

 B. pestis in general appearance. Hence I propose for it the name of 

 Bacillus pestiformis apis. These bacilli usually take up the stain rather 

 more deeply than most of the other organisms met with in these smears, 

 a fact which materially diminishes the labour of looking for them. 

 In pure cultures the bacillus has the following characters : — 

 It is an aerobic, non-motile, Gram negative, non-acid-fast, short, 

 broad bacillus, varying in its morphological appearances upon different 

 media. No flagella could be demonstrated. On agar it grows fairly 

 well, forming in twenty-four hours medium-sized (largest 0*1 cm. in 

 diameter), round, white or slightly yellowish, smooth, glistening, 

 flattened, dome-shaped colonies. On further growth the colonies do 

 not increase much in size, and unless very thickly sown they show little 

 tendency to coalesce. After twenty-four hours' growth the bacilli are of 

 medium length (i-i"5 broad, and with distinctly rounded ends. Many 

 of them are distinctly oval. They have a tendency to stain better at 

 the ends than in the middle (polar staining). Occasionally the lightly 

 staining central portion appears as a distinct band, especially when the 

 organism is lightly stained. After seven days' growth very little general 

 change is noticed, though a few large involution forms make their 

 appearance. On gelatin growth takes place rapidly in the form of 

 colonies, resembling those produced on agar. The organisms are more 

 rounded than on agar, being distinctly oval in shape, and polar staining 

 is not so marked. On potato a considerable raised cream-coloured 

 growth' is produced in twenty-four hours at 37 0 C, which continues to 

 spread. The bacilli are larger than when grown on agar, but the light 

 central band is not quite so well defined. When stained by Neisser's 

 method, a few show polar bodies (metachromatic granules). Involution 

 forms, many of which grow to a large size, appear rapidly, and are 

 very abundant after forty-eight hours' growth. In broth at 37 0 C. a 

 cloudy growth is first formed, but later the medium becomes clearer, 

 and a considerable yellowish, flocculent deposit is produced. A surface 

 film is usually seen after a few days' growth, and may be very marked. 

 If the tube is shaken, the film sinks, or is broken up, but another forms. 

 The bacilli resemble those found on gelatin cultures. No acid or gas is 

 produced in media containing glucose, lactose, saccharose, dulcite, 

 mannite, maltose, dextrin, or glycerine. 



