STOMACH AND INTESTINE 571 



slender, slightly curved bacilli of moderate size, the B. bifidus of 

 Tissier, which often has a bifid extremity, also a somewhat similar 

 organism, B. acidophilus of Moro, but capable of developing in an 

 acid medium, a few B. Welchii, and a diplococcus. The Gram- 

 negative forms are B. coli, B. lactis aerogenes, and cocci. In bottle- 

 fed children the same organisms occur, but the preponderating 

 organisms are Gram-negative of the B. coli type, with many cocci 

 and streptococci. In childhood and adolescence organisms of the 

 bifidus type become less numerous but putrefactive anaerobes 

 become more so, particularly B. Welchii and B. putrificus (coli) of 

 Bienstock ; the latter is a long, slender, Gram-positive bacillus with 

 large terminal spores. During adult life the putrefactive anaerobes 

 tend to become still more numerous, and the putrefactive decom- 

 positions they produce are regarded by Metchnikofi as standing in 

 causal relation to old age. In the healthy adult the stomach, 

 duodenum and jejunum contain relatively few organisms, from 

 the lower ileum to the rectum the intestinal contents are crowded 

 with bacteria, and the greatest number of anaerobic organisms occur 

 here and putrefactive changes are most in evidence. 1 Kendall 2 

 has described the presence of a bacillus (B. infantilis) in large 

 numbers in a condition of infantilism, associated, according to 

 Herter, with chronic intestinal infection. The organism is a Gram- 

 positive, motile, sporing bacillus belonging to the subtilis group. 

 It is aerobic and facultatively anaerobic, grows readily on the 

 ordinary culture media, and ferments dextrose and saccharose with 

 the production of acid only, but lactose is hardly attacked. In a 

 dog and a monkey diarrhoea was produced by feeding with it. 



Urinary and genital organs. The meatus urinarius and distal 

 portion of the urethra contain a few organisms, which increase in 

 number in inflammatory conditions, and Gram-negative cocci may 

 be found (see p. 248). The deeper portion of the urethra, however, 

 is free from organisms, and the bladder is sterile. The genital 

 tract in the female up to the middle zone of the cervix contains 

 organisms, but the uterus and Fallopian tubes are normally sterile. 

 The B. vagince of Doderlein, a large Gram-positive bacillus capable 

 of growing in an acid medium, is frequently present in considerable 

 numbers in the vagina. 



1 See Herter, Bacterial Infections of the Digestive Tract, 1907. 



2 Journ. Biolog. Chemistry, vol. v, p. 419. 



