ANIMAL PARASITES. 43 



the stomach, and -consequently of digestion; but also, at the same 

 time, of the mechanical influence of the friction of the walls and 

 contents of the stomach, in consequence of its peristaltic move- 

 ments. It is to be observed at the same time that the processes 

 last described may be produced not only in the stomach of the 

 rabbit, but also in that of any other animal experimented on, and 

 with the proglottides or eggs of all species of Tania. The latter 

 at least applies to the Tanics, which pass through a vesicular state 

 and to the stomachs of the Mammalia. 



We have now to discuss the question whether the stomach is 

 the only place in the alimentary canal in which the rupture of 

 the eggs and exclusion of the embryos takes place, so that every 

 embryo set free must once have passed the stomach of an animal 

 before it can attain a higher development, I have formerly ex- 

 pressed the opinion that I regarded such an exclusion of the 

 brood as possible, in consequence of the mastication and rupture 

 of proglottides and eggs which had just entered the mouth of the 

 animal, observing at the same time that it now appeared to be 

 established by observation that the brood may sometimes escape 

 in the upper part of the alimentary canal and before reaching the 

 stomach, as in the pig we met with the Cysticerci very abun- 

 dantly in the tongue and oesophagus, although I freely admit 

 that the brood may reach these parts from the stomach. 



That the animal heat alone is insufficient to cause the exclusion 

 of the brood is proved by an experiment made upon a pig at 

 my request by Haubner. Uninjured eggs of Ttenia solium were 

 introduced beneath the conjunctiva of a pig, without producing 

 Cysticercus celluloses in the eye. It is true that to arrive at a 

 definite result in this case the experiment must be made again 

 with crushed eggs, from which the embryos have been completely 

 or partially set free. For as the fresh eggs of Tanice, when 

 placed in large numbers between two glasses, may be crushed, so 

 as to set free at least some of their embryos, without the latter 

 being destroyed, or even injured in any way, the egg-shells, not- 

 withstanding the minuteness of the eggs, may just as easily be 

 crushed during mastication by the teeth of the pig, without the 

 necessary occurrence of any injury to the embryo. I am per- 

 fectly convinced that an embryo which has been set free in any 

 part of the alimentary canal of a warm-blooded animal, will com- 

 mence its migration even from this spot, the animal heat exciting 

 its activity. Therefore, until I am convinced of the contrary by 



