TRICHINAE. 
395 
Trichiniasis of Man and Animals. 
There is, perhaps, no one disease of our domestic animals 
which enjoys a more sensational reputation, or which has been 
more thoroughly investigated, than the disease of swine caused 
by the parasite trichnise spiralis. There is none more worthy the 
attention of the public or the hygienic investigator, than this 
disease of the swine, and other animals, as well as man. Although 
the literature treating upon the disease is of comparatively 
modern origin, still we have no justifiable reason for doubting 
the presence of these parasites in swine at an early date, and 
also, that the consequential disease in man must have existed for 
years, if not centuries, before it came to scientific recognition, 
probably almost coeval with the consumption of pork as human 
food. 
Heller says, “ The history of this disease can be appropriately 
divided into three periods : the first beginning with the discovery 
or observation of the capsule, the parasite not being recognized 
in 1821-28, and including the first description of the capsule by 
Dr. Hilton, of Guy’s Hospital, London, England, in 1835. The 
second period extends from 1835, when Paget discovered the 
eucapsuled parasite, and Owen described it, giving it its name, 
Trichnise spiralis, to the first authentic observation of the disease 
in a human being and the direct establishment of the connection 
with a parasitic disease of swine, which took place in 1860, which 
begun the third period in the history of the disease,” in which 
we ourselves are at present, for, notwithstanding all the valuable 
work done in this field of pathological research, the real key to 
the prevention of the disease, the white stone, which all patholo¬ 
gists desire to acquire, is not yet found, that is, it is not known 
how the swine become primarily infected. 
Leidy was the first to discover the encapsuled parasite in the 
flesh of the pig, in 1847, but as said above, it was not till 1860 
that the connection between the parasites infecting the flesh of 
hogs and man was unquestionably established. 
The principal workers in this important field have been Owen, 
Cobbold, Bristow and others in England, and Luckart, Virchow, 
