ANIMAL PARASITES. 13 



5-varia inveniuntur in Us metamorphoses : 1. Animal maturum. 

 [proglottis). 2. Embryones uncinulati (Grand- nurse; Grossamme). 

 3. Scolex passivam vitam agens sub forma vermis cystici seu 

 Cysticerca, sub forma Platycerca et sub forma Acerca. 4. Scolex 

 activam vitam, agens (Nurse, Amme). 5. Strobila. 



Before proceeding to the closer examination of this subject in 

 detail, I will here give a historical summary of the remarkable 

 attempts which have been made at its explanation. We shall 

 thus see that it is only very recently that the Cystici have been got 

 rid of as a distinct family amongst the Helmintha, and united 

 with the TcenicB. 



The embryos were seen and figured, but not explained by 

 Goeze as early as 1782. The correct recognition and signification 

 of these structures commences with Von Siebold (Burdach's 

 1 Physiologie' ii, p. 201). 



The most important steps of development, in a historical point 

 of view, are the cystic worms {yennes cystici), and we therefore 

 begin with their history. 



The explanation of these hydatid structures has undergone 

 the most varied treatment. As I have mentioned in another place 

 (see my book, 'Ueber die Cestoden im Allgemeinen/ Zittau 1853), 

 it is not improbable that the Mosaic prohibition of swine's-fiesh 

 lias been caused by the circumstance that the measly disease of pork 

 which appears to be particularly rife in the East, even in the 

 present day, was very well known to Moses. To the naturalist, 

 at least, it must appear remarkable that in Lev. xi, verses 5 to 7, 

 Moses has mentioned as unclean, immediatelyafter each other, thres 

 animals, the pig, the hare, and the shaphan, which are still univer- 

 sally known as bearers of Cysticerci. Even if we do not consider 

 the animal " shaphan" to be the rabbit, as the old commentators 

 have done, yet hitherto in all attempts at explaining this word in 

 modern times only animals have been referred to which belong to 

 families particularly characterised by their harbouring Cysticerci. 

 From the point of view above indicated it is a matter of perfect 

 indifference to us whether, in this passage of Scripture, we have 

 to do with a Mus or Scirtetes Jaculus, or with a species oiPedetes 

 (of which as yet only one species, Pedeles Caffer, the Jumping Hare, 

 is known), or with Hyrax Syriacus (a species of the family Lam- 

 nunguia). All that matters to us is, that both the Rodentia, to 

 which the first two species belong, and the Pachydermata, to 



