DYSENTERY BACILLUS. 455 



often shows a polymorphous appearance in cul- 

 tures, but forms no spores. It is Gram-negative. 

 It lives for from 12 to 17 days when dried 

 (Pfuhl) ; direct sunlight kills it in 30 minutes, 

 1 per cent, phenol in 30 minutes, 5 per cent, phenol 

 plus corrosive sublimate (1/2000) almost instan- 

 taneously. It is thought that it may live over 

 winter and cause fresh outbreaks in the spring 

 (Kruse). 



The bacillus is found only in the stools of the 

 infected, in the mucous or muco-hemorrhagic por- 

 tions of which it exists almost in pure culture, few 

 colon bacilli being in the immediate vicinity; it 

 has not been found in the blood or urine. In fatal 

 cases, Shiga found it only in the intestinal ulcers 

 and swollen lymphoid structures and in the mesen- 

 teric lymph glands. Flexner mentions its occur- 

 rence in the liver. The organism, if it reaches the 

 circulation at all, either does so in small quantities, 

 or is rapidly destroyed by the blood. The infection 

 resembles cholera, but differs from typhoid and 

 paratyphoid in this respect. An observation by 

 Markwald (cited by Lentz) indicates, however, 

 that the bacilli may reach the circulation. A 

 woman ill with dysentery gave birth to a child, 

 which died within a few hours. Dysenteric changes 

 were found in the intestines, and the bacillus of 

 dysentery was cultivated from the diphtheritic de- 

 posits on the intestines, from the meconium and 

 from the heart's blood. The organisms must have 

 reached the child through the placenta from the 

 circulation of the mother. 



The intestinal lesions vary from a simple in- Lesions. 

 flammatory hyperemia to rather extensive superfi- 

 cial necrosis (diphtheritic inflammation), which 



