BR. T. S. COBBOLD ON THE LAR&E HTIMAN" FLUKE. 295 



some vertebrate host. To be sure, tbe ultimate bearer need not 

 be the human species ; yet, on the other hand, such a contingency 

 is by no means improbable. Here I would remark that we have 

 very little knowledge of the parasites which take up their abode in 

 the viscera of savages. This ignorance results partly from the fact 

 that these untutored races, as proved by the statements of Kaschin 

 and others, actually suffer much less from the presence of intes- 

 tinal worms than their civilized congeners do, and partly because 

 no one, so far as I am aware, has cared to institute the necessary 

 inquiries in a methodical way. I strongly suspect that several of 

 the human parasites which we now consider to be rare would be 

 found to be abundant, if, by means of postmortem examinations 

 and other methods of investigation, we could be made acquainted 

 with the facts of helminthism as they occur amongst the fish- and 

 raw-flesh eating savage tribes. Of course any person, notwith- 

 standing the utmost care and cleanliness, as in the cases before 

 us, may contract a noxious parasite ; nevertheless, speaking gene- 

 rallj^it maybe said that the measure of internal parasitism affect- 

 ing any given class of people bears a strict relation to the degree 

 of bai'barism shown by such persons in their choice of food and 

 drink, and in their manner of eating and drinking. This state- 

 ment, if true, is not destitute of sanitary importance. Thus we 

 may say to those interested in the matter, " Imitate the Cossacks, 

 Burates, and Abyssinians in their fondness for raw meat, and you 

 will be invaded by Tcenice ; or imitate the very similar habits of 

 North Greenlanders in respect offish, and you will probably enjoy 

 the privilege of entertaining Bothriocephali. If you have a pre- 

 dilection for unfiltered waters, you are likely, sooner or later, to 

 play the role of host to some highly irritating nematode guest ; 

 or, as so frequently happens in Iceland and Australia, you will be 

 particularly liable to contract the so-called -EJcAmococcws-disorder." 

 Clearly it remains to be proved that shell-fish are altogether un- 

 concerned in the matter of human helminthism ; yet I quite be- 

 lieve that danger from this source is limited to certain mollusks 

 living in eastern waters. In all likelihood the Distoma crassum 

 is obtained by the consumption either of fish or of shell-iisli. 

 There remains, however, the consideration that its larvae may pos- 

 sibly reside in minute slugs frequenting vegetables employed as 

 salads. The rarity of fluke-disease (or, at all events, of its recog- 

 nition) is tolerably conclusive against the latter view. At the 

 Bath Meeting of the British Association, in 1864, Mr. Gwyn 



LINN. JOTJEN. — ZOOLOGT, VOL. XII. 22 



