402 TYPHOID FEVER 



conclusive as to the causal relationship between this bacillus and 

 one form of dysentery, a form, moreover, which is both wide- 

 spread and embraces a large proportion of cases of the disease ; 

 and especially of importance is the fact that observations made 

 independently in different countries have yielded practically 

 identical results on this point. 



Bacillus Dysenterise (Ogata). Ogata obtained this bacillus in an 

 extensive epidemic in Japan in which no amoebae were present. He 

 found in sections of the affected tissues enormous numbers of small 

 bacilli of about the same thickness as the tubercle bacillus, but very much 

 shorter. These bacilli were sometimes found in a practically pure 

 condition. They were actively motile, and could be stained by Gram's 

 method. He also obtained pure cultures from various cases and tested 

 their pathogenic effects. They grew well on gelatin, at the ordinary 

 temperature producing liquefaction, the growth somewhat resembling 

 that of the cholera spirillum. By injection into cats and guinea-pigs, as 

 well as by feeding them, this organism was found to have distinct 

 pathogenic effects ; these were chiefly confined to the large intestine, 

 hsemorrhagic inflammation and ulceration being produced. It still 

 remains to be determined whether this organism has a causal relationship 

 to one variety of dysentery. 



BACILLUS ENTEBITIDIS SPOROGENES. 



This organism was first isolated by Klein from the evacuations in an 

 outbreak of diarrhoea following the ingestion of milk which contained the 

 microbe, and it was subsequently found by him in certain cases of 

 infantile diarrhoea and of summer diarrhoea, in certain instances iu milk, 

 and as a constant inhabitant of sewage (see Chapter V.). In films made 

 from the stools in diarrhoea cases where it is present, it can be micro- 

 scopically recognised as a bacillus 1*6 ^ to 4'8 fj. in length and '8 ^ in 

 breadth, staining by ordinary stains and retaining the dye in Gram's 

 method. It often contains a spore near one of the ends, or sometimes 

 nearer the centre. It is slightly motile, and in cultures can be shown 

 to possess a small number of terminal flagella. It grows well under 

 anaerobic conditions in ordinary media, especially on those containing 

 reducing agents. On agar the colonies are circular, grey, and translucent, 

 and under a low power are seen to have a granular appearance. On this 

 medium spore formation does not occur, but is easily obtained if the 

 organism is grown on solidified blood serum, which, further, is liquefied 

 during growth. On gelatin plates liquefaction commences after twenty- 

 four hours at 20 C. It produces acid and gas in bile-salt glucose media, 

 and in peptone-salt solution containing glucose or mannite. Spore 

 formation can be seen to take place in 2 per cent, dextrose gelatin, but 

 the degree seems to be in inverse ratio to the amount of gas formation. 

 Very typical is the growth in milk, and it is by this medium that 

 isolation can be best effected. A small quantity of the material 

 suspected to contain the bacillus is placed in 15 to 20 c.c. of sterile 

 milk, which is then heated for ten minutes at 80 C. to destroy all 

 vegetative bacteria ; the tube is cooled, placed under anaerobic con- 

 ditions, and incubated at 37 C. for from twenty-four to thirty-six hours. 

 If the bacillus be present there is abundant gas formation, and almost 



