554 THE BACILLUS OF QUARTER ILL 



characteristic swelling soon appears surrounded by an cedematous infiltration 

 which rapidly encroaches on the abdominal wall. The animal curls itself 

 up and does not move : its coat is dull and rough and the hair can be easily 

 pulled out from over the oedematous area : death takes place 2 or 3 days 

 after inoculation. 



Post mortem. The characteristic appearances are limited to the local 

 lesion. The site of inoculation is marked by a swelling, and the neighbouring 



connective tissue is infiltrated with an exudate 

 rich in red cells ; the muscles are yellowish or 

 dull red in colour while the fibres are vitreous 



" and degenerated. The centre of the swelling 



is black and sanious and contains bubbles of 



^ gas. The lesions have a peculiar odour, which 



Arloing compared to that of rancid butter, and 



. ^ A contain numerous bacilli. The area of oedema 



f ^ extends for a variable distance around the 



swelling and invades the abdominal and thoracic 



f walls, and the exudate is rich in bacilli but 



,-, contains no leucocytes. The inguinal glands 



FIG. 262.-The bacillus of quarter are .^ematous and swollen. In the peritoneal 



ill. Scraping from muscle Dilute cavity there is a small quantity of a slightly 



Re r ff) fuchsin ' (0c - n ' obj - Ath, cloudy exudate containing numerous bacilli and 



the intestine is frequently congested. The 



blood is almost unaltered in appearance : during life bacilli cannot be found 

 on microscopical examination : after death they are present though few in 

 number even after incubation at 37 C. 



SECTION II. MORPHOLOGY. 

 1. Microscopical appearance and staining reactions. 



The bacillus of quarter ill is a small rod-shaped organism (3-8/* x 1/u) and 

 occurs singly or in pairs : it is straight and rigid and has absolutely square- 

 cut ends. The bacillus is motile but the motility can only be observed under 

 anaerobic conditions in the centre of the microscopical preparations. 



The bacillus of malignant oedema differs from the bacillus of quarter ill 

 in the following respects. It forms long chains, which are never met with 

 either in cultures or tissues in the case of the latter bacillus ; it is also more 

 slender, more wavy, longer and more motile, than the bacillus of quarter ill. 



Spores are rapidly formed in the muscular swellings but may not appear 

 if death occur very soon. The spore is first apparent as an oval refractile 

 spot in the centre or towards the end of the bacillus often giving rise to an 

 appearance like a tennis racquet or clock pendulum. As a rule spores are 

 not found in the fluid which accumulates about the swellings and are never 

 seen in serous exudates : in cultures, both bacilli and spores are formed. 



The relatively large size of the bacillus renders the examination of unstained 

 preparations easy. 



Staining reactions. The bacillus of quarter ill stains readily with solutions 

 of the basic aniline dyes containing a mordant. It is gram-positive and 

 retains the stain by Claudius' method. 



The spores may be stained in the usual way (p. 146). They do not stain 

 in the cold with aqueous solutions of the aniline dyes. 



(a) Cultures. For cultures the most useful stains are carbol-crystal-violet 

 or dilute carbol-fuchsin. 



(b) Smear preparations. Films may be prepared from scrapings from the 



