816 PARASITIC DISEASES. 



its body was found swarming with living trichinse; the ob- 

 servers estimated there were no less than 100,000 in the whole 

 carcase. They also found that rats may be fed occasionally 

 with small numbers of trichinge without in any way disturbing 

 the health; and the inference drawn from these experiments 

 has been, that any animal or man may take live trichinas in 

 small numbers occasionally without injury. These observers 

 further believe that many more human beings than have been 

 hitherto supposed are infected with trichinae; indeed that the 

 majority of us are carrying these worms in our muscles. So 

 sure have they felt of this fact, that one of them ate twelve 

 living trichinae on 20th November 1878, and after more than 

 three weeks had elapsed — when the case was reported — not 

 the slightest effect had been experienced. These gentlemen also 

 discovered that small portions of sulphurous acid dissolved in 

 the brine in which hams are pickled will kill the trichinae. 

 The percentage of acid was not then fully determined, but 

 the amount is so small that it is no detriment to the meat for 

 commercial purposes. 



This worm was first discovered by Professor Owen in 1835 in 

 a piece of a man's muscle, which presented a peculiarly speckled 

 appearance. These specks were found by Professor Owen — as 

 had been previously shown in similar instances by Tiedman and 

 Mr. Hilton — to consist of minute encysted entozoa, which he 

 named Trichina spiralis owing to its hair-like and spirally coiled 

 form; but until 1860 it was only known as a pathological 

 curiosity. At that date, however, Zenker of Dresden showed 

 that, however harmless the encysted parasite might be, the 

 gravest symptoms, and even death itself, might be caused after 

 its reception into the bowels, during the process of its reproduc- 

 tion which then ensued, and during that of the migration thence 

 of the young trichinae into the voluntary muscles. 



It is not yet determined how long the larval trichinae retain 

 their vitality, but there is no doubt that they may live encysted 

 in the muscular tissue for many years, and retain life after the 

 death and putrefaction of their host. They do, however, perish 

 in situ sooner or later, and usually undergo calcareous change. 



When the trichinae capsules are swallowed, they are dissolved 

 liy the gastric juice, and the contained parasites set free ; they 

 then rapidly undergo development, and attain sexual maturity, 



