Bacteria of the Digestive Apparatus 65 



may be no bacteria in the upper part of the jejunum, but 

 in most cases Bacillus lactis aerogenes and bacilli of the 

 colon groups are found. These increase in number as the 

 iliocecal valve is reached. The cecum shows large num- 

 bers of colon bacilli. The rectum contains, in addition, 

 many putrefactive organisms, such as Bacillus, putrificus, 

 Bacillus proteus vulgaris, members of the Bacillus subtilis 

 group, and acid-producing organisms, such as Bacillus 

 acidophilus. 



An interesting and thorough study of these organisms 

 of the bowel and their distribution has been made by Kohl- 



Fig. 6. Sarcina ventriculi (Migula). 



brugge.* The total number of permanent residents is not 

 known. During infancy the predominating organism seems 

 to be Bacillus lactis aerogenes; during adult life, Bacillus 

 coli. Streptococci, especially Streptococcus coli gracilis, 

 are also very common, if not invariable, inhabitants of the 

 intestine. The total bacteria that finally appear in the 

 feces, according to the studies of Strasburgerf and Steele,{ 

 may reach the enormous figure of 38 per cent, of the total 

 bulk. 



* "Centralbl. f. Bakt.," etc., Bd. xxx, 1901, pp. 10 and 70. 

 t "Zeitschrift fur klin. med.," 1902, XLVI, 5 and 6; 1903, XLVIII, 

 5 and 6. 



J "Jour. Amer. Med. Assoc.," Aug. 24, 1907, p. 647. 



5 



