826 



A PIECE OF CHALK. 



To mount the specimens for the microscope all that remains to be 

 done is to take as many as will lie on the point of a luiife and boil them 

 for a short time in a test tube containing a little turpentine. This la 

 done to expel the air from the shells. Transfer a few of the specimens 

 to the centre of a glass slip, add a spot of Canada balsam, and 

 immediately place a thin cover glass on, and when dry finish off according 

 to taste. The slides thus inexpensively provided will then be ready to 

 answer the enquiry " What does the chalk contain ? " 



PARASITES OF MAN.* 



BY T. SPENCEK COBBOLD, M.D., F.K.S., ETC. 



[Continued from page 297.] 



The few nematoid parasites that remain to be considered comprise 

 Beveral rare and interesting species, and likewise two of the commonest 

 intestinal worms. What I have incidentally advanced respecting the 

 strange way in which the old writers confounded Guinea-worms with 

 little serpents, finds noteworthy confirmation in the circumstance that 

 the great strongyloid kidney-woi-m has also been looked upon as a 

 species of venomous ophidian reptile. Facts of this order, if duly 

 weighed, inevitably cause us to modify onr interpretation of the state- 

 ments made in ancient records. Thus, to retui-n to the Guinea-worm. 

 Whatever good the theosophical remedies recommended and enforced by 

 Moses may have accomplished for the human victims suffering from the 

 attacks of " fieiy serpents," or Dracunculi, it is to be feared that no 

 similar remedial measures of the mystical kind could be rendered 

 available in the case of animals bitten by parasites that have been 

 regarded as renal serpents. It is fortunate, indeed, for man that the 

 great kidney-worm ( Kustmngylua gigas) has only once been detected in 

 the human body. If this formidable entozoon, capable of attaining a 

 length of three feet, were as common in man as it is in certain animals, 

 no doubt the superstitious people of southern climes would readily 

 invoke clerical aid in view of obtaining miraculous cures. Possibly a 

 mitigation of their sufferings might follow such exhibitions of liumau 

 sympathy and trust. The case of animals, however, is very different. 

 The unfortunate wolves of the Pyrenees cannot, of course, bo expected 

 to secure any very large amount of sympathy ; nevertheless, it is the 

 business and duty of the helminthologist to point to the causes of the 

 Bufferings of all kinds of animals, whether wild or domesticated, and so far 

 as lies in his power to suggest the means whereby their sufferings may be 

 mitigated. Not only do solitary and large nematoid parasites take up 

 their abode in essentially vital organs of the body, and thus secure the 

 slow destruction of the host, but the minutest forms of the same group 



♦ Commnniciitecl by Mr. Hnghes to the IMicroscpical Section r f the Birminsham 

 Natural History and Microscopical Society, November I'Jth, 1H78. On Pr. Cobbold's 

 behalf, Mr. Hiinhts e.xbiiiited a shdo shovviut: iiinle and fennde examples of the 

 destructive parasite iDuchmius duodenalis) which causes theKgyptiau chlorusia. 



