56 
F. S. BILLINGS. 
reich Saclisen,” 1862, p. 118. “ One cannot speak of a trichin- 
disease in swine, which characterizes itself by distinct and pa¬ 
thognomonic symptoms. In this relation the trichinae deport 
themselves in a manner similar to the cysticerci, measles.” 
Leisering made some feeding experiments with triclnnous flesh 
in a horse, but the most exact examination failed in discovering a 
single representative of the parasites in the flesh. It may also be 
casually remarked that fowls present some unknown hindrance 
to the invasion of their flesh by the embryonal trichinae. I made 
quite a number of experiments with hens, feeding them for two 
weeks almost entirely on pork profusely infected, but was unable 
to find a single trichinae in their muscles. Further research must 
endeavor to discover the cause of this singular immunity ; whether 
it is that the triturative power of the gizzard is sufficient to kill 
the trichinae, or what it is, which prevents invasion ; further, are 
all varieties of domestic fowls thus immune to invasion? IIow 
do swine become infected under the natural order of tilings, or in 
other words, from whence do they derive the trichinae % 
That the trichinae gain access to the organism by means of the 
mouth and alimentary canal is placed beyond all doubt. 
Notwithstanding the apparent negative of the above quoted 
Berlin experiments, we have the very highest other authorities af, 
firming from positive observation, that intestinal and embryonal 
trichinae do leave the autositic organism with the fceces. 
Leuckart says, vol. II, p 557, “ As the sexually matured 
trichinae are accumulated in great numbers in the intestines, and 
as the irritation caused by them leads to the development of a 
more or less intensive diarrhoea, so is it evident that the young 
must be frequently passed with the foeces. And not only free 
embryos, but also pregnant females are subject to this destiny, 
which has been sufficiently attested by such observers as Luck- 
art, Yogel, Kuhn, Gerlach and others.” “ It is this form of mi¬ 
gration, which, under favorable circumstances, also contributes to 
the distribution of the trichina},” p. 558. “ In fact, Haubner and 
Gerlach mention cases where they intentionally caused the infec¬ 
tion of young (non-infected) swine by causing them to cohabit 
with known trichin-infected ovres.” 
