its discovery did not have to await the invention of the 

 microscope. HIPPOCRATES, the Father of Medicine, mentions 

 it as familiar in his day, and seems to have treated many cases. 

 Innumerable authors and scientists have since written of it ; 

 and, it may be truly said, that the references to this minute 

 animal from the clinical and zoological points of view would 

 fill a library of respectable dimensions to overflowing. 



Zoologists and the Threadworm. 



Zoologists have classified, and re-classified the parasite, 

 and its life history has been painstakingly investigated. Its 

 anatomy has been described in detail, and its physiology has 

 engaged the earnest attention of many eminent biologists. 

 Its parts and organs have been measured with inconceivable 

 care, and the measurements have been recorded to the smallest 

 fraction of a millimetre 1 . Its digestive, reproductive and other 



1 This was done by KUECHEN- 

 MEISTER, some of whose figures are 

 appended : Mas : 2-05 mill., ad 2-5 

 mill., ad 3-37 mill, longus (si caudam 

 semper curvatam tamquam linea 

 recta extensam mensus es) ; 

 in capite una cum appendicibus 

 0-094 mill., sine appendicibus 

 0*024 mill., medio in corpore 

 123 mill., in cauda 0-023 mill, 

 latus. . . . (Esophagum sequitur 

 brevis tubi intestinalis strictura 

 0-008 mill, longa, et 0-016 mill lata. 

 Postea sequitur ventriculus 0-115 

 mill, longus, et 0*065 mill. Jatus, 

 cum valvularum apparatu cog- 

 nito ; tubus intestinalis paulo 

 post ventriculum latitudinis 0-057 

 mill, est, ad anum vero usque ad 

 0-008 mill. . . . Penis simplex, 0-057 

 mill, longus, ad basin 0*008 mill., in 

 apice vero semper ad hamuli 

 instar recurvato, latitudinis (adul- 

 timum 0-003 mill). 



Femina t 7*84 ex aliis ad 10 

 mill, longa ; in capitis apice cum 

 appendicibus 0-196 mill. ; sine 

 appendicibus 0-065 mill. ; in medio 

 corpore 0-49 ad 0-59 ; extremitas 

 caudalis acutissima. Longitude 

 caudae (i.e., partis inter anum et 

 apicem) 1-798 mill. ; latitude 

 caudae ad anum ipsam 0-2f> mill., 



inde diminuitur. (Esophagus 0-65 

 mill, longus, in capitis apice 0*065 

 mill., in parte posteriore 0*098 

 mill, latus. Strictura tubi intes- 

 tinalis pone oesophagum uti in 

 maribus perbrevis et 0*028 mill, 

 lata. Ventriculus 0*172 mill, et 

 longus et latus, interdum lati- 

 tudine aliquid minor. Vagina 

 ex Dujardini mensuris 1-8 mill., 

 ex meis ad 1-64 mill, pone caput 

 sita ; in vivis 1-06-1-2 mill, longa 

 et O'll mill, lata ; cum foramine 

 latitudinis 0-13 mill., longitudinis 

 0.15 mill. ; uterus duplex, cujus 

 ramus posterior 2-0 mill., cujus 

 anterior 1-35 mill, longus ; ramo- 

 rum ovulis impletorum latitude 

 ad 0-4 mill, et ultra ovulis expulsis, 

 0-2 mill. ; ovarium duplex, in 

 transitu uteri in anum 0-03 mill, 

 latum. 



Ovula fere oblonga non sym- 

 metrica ; ex Dujardini mensuris 

 0.055 mill, lata et 0*064 mill, 

 longa, ex meis media in parte 

 ovulorum 0*029 mill, in apicibus 

 circiter 0-012 mill, lata et 0-05 

 mill, longa. . . . (KUECHEN- 

 MEISTER, G. F. A., Die in und an 

 dem Koerper des lebenden Menschen 

 vorkommenden Parasiten, Leipzig, 

 1855, vol. i., pp. 276-8.) 



