INFLUENCE OF TIME AND LOCALITY. 165 



food, and especially of raw flesh, insects, and snails, the close associa- 

 tion of man and beast, and, in short, all the external characteristics of 

 savage life, are, as we have seen, most important causes of parasitic 

 diseases, and facts, so far as we know them, bear this out. Nowhere 

 are intestinal worms more frequent than among savage peoples, especi- 

 ally in the tropics, as has been long ago sufficiently established, and 

 lately confirmed by travellers and physicians, especially in the case of 

 Africa. In Abyssinia, for example, every inhabitant, male or female, 

 is infested with intestinal worms from his fourth or fifth year. Similar 

 results might be given in regard to the American slaves, the Esqui- 

 maux, and the Buratis, among the lower class population of the East 

 Indies. Of course the same parasites do not prevail throughout. The 

 negroes of the West Indies are specially plagued with Ascaris; the 

 Abyssinians most commonly harbour Tcenia, due, as has been sup- 

 posed since the time of Bruce, to their general use of raw meat. Since 

 the flesh of swine is avoided by the Abyssinians, it is of course not 

 Tcenia solium, but Tcenia saginata, which occurs. The latter is associ- 

 ated with the ox almost throughout the world, while the former, like 

 Trichina, is specially prevalent in those lands where swine are generally 

 bred. 1 A difference may even be observed in neighbouring districts 

 like North and South Germany. In Berlin Tcenia solium, and accord- 

 ingly its related Cysticercus cellulosce, are not at all rare in man, but 

 both so uncommon in Vienna that physicians sought long in vain for 

 the latter, and not being in a position to distinguish Tcenia saginata 

 from Tcenia solium, regarded the reports of the Berlin physicians as 

 to the frequent occurrence of bladder-worms in the eye with uncon- 

 cealed distrust. We can similarly understand how the famous hel- 

 minthologist Bremser, living in Vienna, was never convinced of the 

 existence of a circle of booklets in the human tape-worm till Eudolphi 

 sent him the head of a Tcenia solium from Berlin. Where the use of 

 flesh decreases, the supply of certain Helminths becomes less copious, 

 the worms themselves being less numerous ; but the difference may 



1 In Denmark Krabbe found Tcenia solium only 53 times in 100 cases of tape-worms, 

 T. saginata 37 times, T, cucumerina once, and Bothriocephalus 9 times. The proportions 

 were similar in Giessen, where out of 57 tape-worm patients only 12 were infected with 

 Tcenia saginata. On the other hand, among 35 tape-worms observed in Florence by 

 Marchi, there was only a single Tcenia solium. But these proportions vary according to 

 circumstances. Thus Krabbe writes to me that since 1869, up to which time the above 

 numbers held true, T. saginata has become relatively more frequent in Copenhagen and 

 its surroundings. Out of 78 new cases since that time, there were only 16 of Tcenia 

 solium, but not less than 46 of T. saginata, 4 of T. cucumerina, 10 of Bothriocephalus. 

 Krabbe looked for the cause of this partly in the Trichina-panic, which had considerably 

 restricted the use of raw swine's flesh, partly in the greatly increased use of raw beef in 

 illnesses. And in Northern Germany, according to my personal experience, the occurrence 

 of Tcenia solium has in a decennium become much less frequent. 



