ox THE DEVELOPMENT AND MIGRATIONS OF THE ENTOZOA. 113 



hydatids {Ciisticercus pisiformis) commonly found in rabbits. I offer the fol- 

 lowiiij? facts, therefore, partly in confirmation of previously ascertained results. 



On the 21st November, 1862, I administered to a dog one immature 

 Cysticercus-vesicle taken from the abdominal cavity of a rabbit ; and to the 

 same dog I also gave, on the 24th of the same month, four mature 

 examples of Ci/sticercus piisiformis taken from the mesentery of another 

 rabbit, one of the larvae being injured. On the 28th of November the dog 

 was destroyed; and the result gave three examples of immature Tcenia 

 serrata, each measuring about half an inch in length. Their size indicated 

 clearly whence they were derived, whilst the non-development of the 

 injui-ed Cysticercus, as weU as that of the imperfectly developed larva, is 

 sufficiently accounted for, and accords with my previous experience. 



On the 19th January, 1803, on the 6th of Pebruary, and again on the 

 23rd of the latter month, I administered several mature examples of 0. 

 pkifonnis to the dog, wliich was subsecpently liberated, without my being 

 able to ascertain the result of my worm-feedings. 



On the 20th February, 1863, I gave to another dog eight immature larva) 

 taken from the abdomen of a rabbit ; and again, on the 6th of March suc- 

 ceeding, two mature larva) (C. pisiformis) were given to the same dog. 

 This animal was destroyed on the ISth of March, and the result was entirety 

 satisfactory. There were two examples of Taniia serrata, each aboiit four inches 

 in length, none of the migrating or immature larvte having continued their 

 development. 



On the 27th May, four fresh Cysticerci from a rabbit were given to 

 another dog, which, on being destroyed on the 3rd of the following June, 

 was found to contain four examples of Tcenia serrata. In this instance, I 

 believe, only one of the Cysticerci had developed into its strobila-form, one 

 being about three inches in length : the others were upwards of a foot 

 long, and could not, I presume, be referable to the three other larvae. This 

 experiment, therefore, was partially negative. 



3. Tcenia marginata. — On the 5th November, 1862, I fed a monkey with 

 eggs of this worm ; but he swallowed only a very small portion of the 

 potato in which I had placed them. The destruction of the animal on the 

 5th of February, 1863, only yielded a negative result. 



4. Tcenia cucumerina. — On the 8rd November, 1862, I fed several cock- 

 roaches (Blcttta orientalis') with mature proglottides of Tcenia cucumerina. 

 Subsequent careful dissections of these insects, at various intervals, failed 

 to reveal the existence of Cysticerci within their tissues. 



On the 7th of November, 1863, and again on the 12th, I fed other Blattce 

 with proglottides and eggs, mixed vrith sugar, treacle, potatoes, and bread ; 

 but these administrations only gave negative results. 



On the 2Uth January, 1864, I removed a proglottis of the so-caUed Tcenia 

 elliptica (in the act of migrating) from the external surface of the body of a 

 cat. I placed it on glass, and noticed that it discharged eggs during its 

 movements. The proglottis was subsequently broken up and mixed with 

 paste. Five or six Blattce were next captured ; and, on being brought in 

 contact with the food, they very soon devoured the paste and all the 

 enclosed fragments of the proglottis, including the eggs. Forty-two hours 

 afterwards I dissected one of the larger cocki'oaches, and found at least one 

 hundred tapeworm eggs in its stomach. Each egg contained a six-hooked 

 embryo. There were one or two empty shells ; but I did not succeed in 

 finding a free embryo. Here the experiment ended ; for the other Blattce 

 successfully made their escape a few days afterwards. 



1864. I 



