The cysticercus of the pig, when introduced into man, becomes a tænia with as great certainty as the seed of a carrot will produce this plant if sowed in suitable soil. The observation had been for a long time made without any explanation being given, that this parasite especially shows itself among pork butchers and cooks. This is because these persons, more frequently than others, handle raw pork. The same observation has been made respecting children who have made use of the gravy of raw meat. Minced raw meat (_conserve de Damas_) has been prescribed with success in chronic diarrhoea. The tape-worm has often been known to make its appearance after this treatment, as 216 may well be supposed. Tænia helminthosis is constant and general in Abyssinia, and they there commonly eat raw beef. Those who do not eat meat, as the monks of certain orders there, who live only on fish and flour, never have the tænia. Ruppell and many others have noticed this fact. Mons. Küchenmeister says that at Nordhausen, in the Hartz, as well as throughout all Thuringia, measles are very prevalent among pigs; and as the people are in the habit of eating minced pork, both raw and cooked, spread on bread for breakfast, this country may be looked upon as the Abyssinia of the north. The doctor at Zittau caused a man who was condemned to death, to take, seventy-two hours before his execution, some cellular cysticerci from a measled pig; and he found in the duodenum of the man four young tæniæ, and six others in the water in which they had washed the intestines. The latter had no hooks, but those of the former had some in every respect similar to those of the _Tænia solium_. We have ourselves caused a pig to swallow eggs of the tænia, and have given it the measles. Messrs. Küchenmeister and Haubner, who were ordered by the government of Saxony to make some experiments, also caused three pigs to swallow eggs of the _Tænia solium_, and two of these were affected with measles. A piece of flesh, weighing 4-1/2 drams, contained 133 cysticerci, which amounts, for 22 German lbs., to 88,000 cysticerci. The use of raw pork will produce tæniæ more readily than raw beef. Dr. Mesbach has given the following instance in support of this fact. At Dresden, a father and his children regularly ate, at their second 217 breakfast, raw beef, but one day they took pork instead, and eight weeks afterward one of the children, when in the bath, voided two ells of _Tænia solium_. The etiology and prophylaxis of the solitary worm, that is to say, its mode of introduction, and the means of protecting ourselves from it, are clearly indicated. It is sufficient to introduce one of these vesicles into the stomach in order to have the tape-worm. The experiment has been made: young men have ventured, in the interests of science, to swallow some, and have ascertained how many days were required for the parasite to be sufficiently complete to give off segments with the feces.