BACTERIOLOGICAL EXAMINATION OF MATERIAL 225 



approaches more and more that of the adult, into the characteristic 

 flora of the adult. 



In the earliest days during the stage of "adventitious infection/' 

 when the child is getting its first bacteria from the air and subjects 

 with which its mouth comes in contact, the bacterial flora is de- 

 termined largely by accident. 



When the child begin to take food, it is of great importance 

 for the determination of the bacterial flora, whether it is being 

 breast fed or being fed on artificially modified cows ' milk. 



In breast fed children, the upper part of the small intestine will 

 usually contain enterococcus, streptococcus lacticus, and a general 

 predominance of the coccoid form. Lower down toward and behind 

 the ileocecal valves, the B. lactis aerogenes and the Colon bacilli 

 appear. In the lower parts of the cecum and the rectum, the anaero- 

 bic Bacillus bifidus of Tissier and similar anaerobes predominate, 

 and many proteolytic bacteria may be present. 



In contrast to this, in artificially fed infants, the bowel is rela- 

 tively richer in the Colon group, and the B. aerogenes type; B. 

 mesentericus and other anaerobic spore formers will be present in 

 considerable numbers, and in the lower bowel the B. bifidus types 

 are largely replaced by Colon bacilli, B. acidophilus and similar 

 organisms. Very early there may be also present in children a 

 curious little tetanus-like organism spoken of as Bienstock's B. 

 putrificus. 



Tissier, who has done a great deal of work on this problem, 

 described the flora of a five year-old child in which the gradual 

 transition from the milk to the mixed diet was taking place as 

 follows. We quote from Kuster. 17 "Constant fundamental flora, 

 B. bifidus, enterococcus, Colon bacillus, B. acidophilus. Variable 

 adventitious organisms, B. perfringens, cocci, and a number of other 

 Gram-negative bacilli, together with some yeasts.'* 



As adult life is attained, there is a gradual relative increase 

 of organisms of the Colon type, which eventually constitute about 

 75 per cent of the intestinal bacteria. 



In the normal adult the stomach is usually sterile. The duodenum 

 contains a few cocci and Gram-positive and negative bacilli, not of 

 the Colon type. There is a gradual numerical increase of bacteria 

 downward. In the jejunum, or upper ileum, the Colon types begin 



17 Kuster, Kolle and Wvssermann, 2nd, Edition, Vol. 6, p. 469. 



