42 INFECTIONS OF THE DIGESTIVE TRACT 



(2) a bifid form, and (3) a cephalated (knobbed) or 

 headlet form. The simple form is by far the commonest, 



in the course of his studies in the name "punctate " bacilli. These 

 unevenly colored bacteria are commonly stained in their middle 

 portion, while their ends are colorless, and this condition arises 

 presumably on account of a central concentration of the proto- 

 plasm, which leaves relatively empty adjoining spaces. There 

 are, however, other variations in the distribution of the colored 

 protoplasm within the bacillus, which it is unnecessary to describe 

 here. Frequently it will be noted that several bacilli are joined 

 end to end, forming one long, unevenly stained structure. As 

 the decolorized portion of the simple form of B. bifidus is still 

 able to take up the counter-stain (e.g. carbol f uchsin) with avidity, 

 we get apparently Gram-negative bacilli in those cases where the 

 protoplasm has been rarefied throughout. 



In addition to the simple forms of bifidus, a careful examination 

 of the smear will sometimes reveal the presence of the bifid form 

 from which the group takes its name. Sometimes the bifid form 

 is very scanty or absent; at times it is moderately abundant; 

 but it is never in health the dominant form. As pointed out by 

 Moro, the bifurcation is peculiar in these bacteria in being a true 

 division of the end or ends of the organism rather than a lateral 

 branching, such as one sees in certain actinomyces. It is not 

 necessary to describe here the numerous variations in morphology 

 exhibited by these bifid bacteria. (For fuller details see Moro, 

 " Morphologische und biologische Untersunchungen tiber die 

 Darmbakterien des Sauglings," Jahrb. /. Kinderheilk., Ixi, p. 687, 

 and p. 870, 1905; also Tissier, loc. cit. and Ann. de VInst. Pasteur, 

 xix, p. 109, 1905; and Rodella, " Repartition des Microbes dans 

 Tlntestin du Nourrison," Ann. de VInst. Pasteur, xix, p. 404, 1905.) 



A third form of bacterium, which apparently belongs in the 

 same group with the simple and bifid forms just described, is 

 characterized by a small enlargement at one or both ends the 

 headlet or "Kopfchen" form. These headlet bacteria are seldom 

 numerous in the faeces of normal nurslings, and it is usually 

 necessary to look carefully over the field to find them, although 

 they are seldom quite absent. The bodies of these bacteria are so 

 like the bodies of the simple form in their morphology that one is 

 tempted to regard them as simply slightly modified examples of 

 this simple form a view which is borne out by the results of 



