642 BACTERIA OF THE INTESTINAL TRACT 



croaerophilic, while the other is a facultative anaerobe. Furthermore, agar colonies 

 of the Tissier organism are solid and disk shaped, whereas those of the Moro bacillus 

 are as a rule of the extremely fuzzy "X" type or the more nearly regular and slightly 

 fuzzy "Y" type. They are always very small, delicate colonies (both are slow to de- 

 velop in artificial media), and require carbohydrate for growth. Both grow in milk, 

 with the production of lactic acid and, as a rule, a soft curd. 



MICROCOCCI 



The most common and best known is the Enterococcus of Thiercelin, or Strepto- 

 coccus fecalis. A complete description of this coccus form was published recently by 

 Dibble.' It is a common inhabitant of the intestine at almost all ages, and occurs 

 there as a diplococcus, in short chains, and occasionally singly. It produces more or 

 less typical, small, smooth, granular streptococcus colonies on sugar agar, which 

 usually grow to larger size, however, than colonies of pyogenic streptococci. This 

 organism rapidly grows in milk and produces a curd not very unlike that of L. acid- 

 ophilus. Other streptococcus forms may also be present, but their significance as def- 

 inite fecal organisms needs further study. 



Staphylococci also occur in the intestine. These are of much less prominence than 

 the Enterococcus. Schiller found that they are present in the intestine of human 

 adults, but that they are quite rare in infants. Streptococci of the ordinary hemo- 

 lyticus tj'pe may be found occasionally, having come from the mouth. 



ANAEROBES 



The most common and best-known intestinal anaerobe is CI. welchii. This inter- 

 esting, actively fermentative organism is often present in enormous numbers, and 

 may almost be said to be ubiquitous in man and animals. It sporulates abundantly 

 in the intestine, and may be isolated readily for this reason. The intestine is believed 

 by many to be a normal habitat of CI. tetani. Noble found some horses to be carriers, 

 and Ten Broeck observed it to be a common inhabitant of the intestine of Chinese 

 coolies in the Orient. 



Other anaerobes are often present; but few, if any of these, carry on a permanent 

 existence in the intestine; in other words, they are adventitious, transient organisms. 



Bacteria of the fusiformis and spirocheta types may cjuite often be seen micro- 

 scopically, but they appear to resist the ordinary methods of artificial cultivation. 

 Spirochetes have been observed in the intestinal contents by various observers (Kuisl, 

 Miller, Macfie, Wolbach, and Parr). In some instances they were cultured, but there 

 may perhaps be a question as to whether the cultures were absolutely pure. 



PROTEUS GROUP 



Organisms of the Proteus vulgaris type may be recovered occasionally from feces. 

 It is doubtful, however, if they are present in large numbers or with any degree of 

 frequency, except here and there perhaps in connection with certain pathological 

 conditions, as some have claimed. 



l)il)blc, J. II.: J. Path. ^ Bad., 24,3. 1921. 



I 



