118 PARASITES OF MAN. 



PAEASITES OF ]\IAN 



BY T. SPENCER COEBOLD, M.D., F.E.S. 



[Continued from page 99.] 

 In addition to tlic eight Cestodes noticed in my previous communica- 

 tion, all of which belong to the genus Tccnia, we find the human host 

 liable to entertain several BothriocephaJi. These are readily distinguished 

 from ordinary tapeworms, not only by the absence of true suckers on the 

 head, but also by the circumstance that the reproductive openings are 

 placed on the ventral aspect of the proglottides, and in the median line. 

 The classification of the Cestodes, as a whole, requires revision, but no 

 Boological arrangement will stand that is not based on the examination of 

 a large number of types. It may be that the out-of-the-way tj-pcs are 

 difficult to get at and comparatively rare ; nevertheless it is just these 

 aberrant tj^pes that are wanting to the Cestode systematist. The hard 

 and fast line drawai between the armed tapeworms and the unarmed 

 forms cannot be allowed to remain, since laidimentary booklets have been 

 found attached to the margin of the supplementary suckerlet or central 

 disk of the beef tapeworm. Of course, as a matter of mere convenience 

 it is very useful to separate the hooked and bookless Tjenioj, but the 

 separation is not fitting as a primaiy basis of classification. In like 

 manner the snouted or proboscis-bearing tapeworms, ( Rhi/iichotceniadw,) 

 considered as altogether distinct from the tapeworms that do not possess 

 any proboscis or rostellum, ( Arliynchotccniadee,) cannot be accepted. 

 Of far more significance and value is the proposal that we 

 should divide the tapeworms into two sub-orders, based on . the 

 characters of the egg-shell. This originated with Dr. Weinland of 

 Frankfort. Thus, for the thick or hard-shelled tapeworms, he proposed 

 the term ScIerolc2)tidota,!md for thin-shelled forms the term Malacolcptidota. 

 The eggs of the former reqxiire the action of the gastric juice of 

 vertebrates to dissolve their shells, whilst the eggs of the latter readily 

 hatch within the stomach of evertebrated animals, such as moUusks and 

 insects. Quite recently, astonishment was expressed (in the pages of a 

 scientific journal) that herbivoi'ous animals (rabbits and hares) should 

 Buffer from the presence of tapeworm. It was evidently unknown to 

 the writer that the larvoo of tapeworms (Cysticerci) are foimd in many 

 other kinds of food than meat. To be sure, as Melnikow's discovery of 

 the larvae of Tcenia cucumerina in the louse of thcHog, (Trichodectcslatm,) 

 amply shows, "measles" are not necessarily swallowed as part 

 of the ultimate host's food, but may be taken into the stomach 

 accidentally. Respecting the question (raised by the President at the 

 last meeting of the Section) as to the temperature necessary to 

 destroy the eggs of tapeworms, I have no special information to offer, but 



* Read before the Microscopical Section of the Birminftham Natural History and 

 Micropcopical Society, Kith April, 1878. The specimens exhibited by I\Ir. Hughes on 

 Dr. Cobbolil's behalf wore Bothriocoithalus latJis and portions of li. cnriUitiis ; also 

 part of a large raatorniU hydatid atid one daushter-vesicle, toRother with a 

 microscopic slide, showing the so-called Echinococcus heads and hooklets. 



EnnATOM IN Apiiil NujiriEU (p. 98, lino 0).— For " muscles in the beast and in 

 the connective tissues," read " muscles in the heart, and in the connective tissues." 



