DESCRIPTION OF BOTnEIOCEPHA.LUS CEISTATUS. 735 



its head. The amount cast off in the year, in pieces usually 2 to 4 feet 

 long, may accordingly be estimated at about 60 feet. If the worm 

 were expelled almost as far as the head, six to eight weeks would 

 sometimes suffice to allow it to grow to 6 to 8 yards. At all events, 

 the growth of Bothriocephalus is much quicker and more energetic than 

 in the case of the large-jointed Tcenice of man. 



It is probably, too, on account of the unusual length of the worm 

 and the great flexibility of its body, that it is by no means so easy to 

 expel as one would imagine from the weak development of the attach- 

 ing apparatus. 



It is hardly possible to state with certainty how long the parasite 

 may remain in man. It is probably not behind the large-jointed 

 Tosnice in this respect. At all events its existence may extend over 

 many years. Bremser mentions the case of a native of Switzerland, 

 who had lived for twelve years out of his native country, but had 

 observed the presence of the worm only a year before, and as the 

 stretches of joints contained in the faeces may easily escape notice, it 

 is by no means impossible that the parasitism had extended over an 

 even longer period. Mosler also reports two cases of Bothriocephalus, 

 one of which was six years old, and the other probably fourteen, but 

 certainly ten.^ Since the ova, as we have seen, are allowed to escape 

 in such great numbers that the uteri in the last joints, if these have 

 remained fof some time in connection with the rest of the chain, are 

 usually quite empty, the examination of the fseces demonstrates the 

 presence of the parasite with absolute certainty, even when it has 

 been otherwise unobserved by the host. As a rule, however, the 

 parasite soon makes its presence felt — according to Braun's experi- 

 ment, three weeks after inspection — by occasioning difficulties in 

 digestion, like those caused by the larger Tccniw. These effects (gripes, 

 loss of appetite, sickness, &c.) apparently follow the presence of 

 Bothriocephalus with more certainty and intensity than that of Tcenite, 

 sometimes, or even frequently, producing nervous disorders, especially 

 in women. Prolonged persistence occasionally produces marked ema- 

 ciation, while other cases occur in which the worm does not cause the 

 slightest inconvenience. The possibility of self-infection is seen, of 

 course, to be excluded by the life-history of the parasite. 



P Botlirioceplialus cristatus, Davaine. 



Davaine, "Traits dea Entozoaires," second edition, supplement, p. 928 : Paris, 1877. 



Some years ago Davaine described under the above title a form of 

 Bothriocephalus which he regards as representative of a distinct species, 

 1 Virchow's Archiv f. path. Anat., Bd. Ivii. 



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