1893.] MICROSCOPICAL JOURNAL. 157 



re;ichin*j their final lesting-plncc in the muscles, and after a 

 tew months the c\st is formed around tliem, rcnderinji; them 

 liarmless to the peison l)earin<i^ them. In this encysted state tliey 

 retain tlieir vitality, it is said, for main years, and when the flesh 

 of the animal is eaten by another they attain protluce their yoimjf 

 and pass tinoujjh the same cycle. 



One authority briefly describes them thus : •• Tiie lite-history 

 of tiichina' is contained in a cycle, which includes at least two ani- 

 mals, the first beinj^ that in which the parasite is born, partly ma- 

 tured, and then enclosed in a li\ injr tomb, and the second, that in 

 which it is set free and in which it becomes fully matured, pro- 

 pagates its species, and dies." 



It is during the migratory stage that they produce their charac- 

 teristic symptoms in the human subject. The symptoms begin 

 a few days after eating the meat, with feyer, loss of appetite, gas- 

 tric irritation, and diarrhoea, and is often mistaken for enteric 

 feyer, while the violent muscular pains resemble rheumatism. 

 These symptoms last from 4 to 8 days, varying in intensity ac- 

 cording to the extent of the invasion. 



Nothing is known as to the origin of this parasite. Hogs get 

 them from eating rats, but rats do not seem to be the original 

 source, for when hogs are absent rats contain few trichinie. It 

 has been said that i in 50 hogs contains trichinae, and i in 10 rats is 

 trichinous. This being the case, we might ask, why are cases of 

 trichinosis so ra're in a country where so much pork is eaten ? For 

 two reasons : first, the worm is killed by a moderate heat, 140^ 

 Fahrenheit, so that any ordinary cooking makes it safe to eat trichi- 

 nous meat; second, all the large Eastern packing-houses employ 

 persons to examine small pieces of the diaphragm of each hog 

 killed, and those found trichinous are consigned to the soap vat. 

 All cases of trichinosis in man arise from eating raw or smoked 

 meats. Salting and smoking do not kill the worm, and salted or 

 fresh pork should be well cooked. 



The most frequent source of the disease is the so-called bologna, 

 made from trimmings of the hog mixed with beef. The ham and 

 shoulders are less apt to contain them than the sides. 



Trichinae may be easily detected by taking a small piece of the 

 suspected meat and placing it between two glass slides and press- 

 ing it until the fibres are thoroughly separated, or by teasing it 

 out with needles. A minute quantity of distilled water should be 

 placed on the specimen before it is pressed out. For permanent 

 microscopic mounts, the flesh must be cut into pieces about :|- inch 

 cubes and hardened in alcohol, then cut into thin sections and 

 stained with carmine or picro-carmine, and mounted in Farrant's 

 solution or balsam. 



Another method described in one of the microscopical journals 

 is said to be very good. Macerate a small piece of the trichi- 

 nous muscle in cold water for one day, then tease it out with 

 needles ; place it between two glass slides and bind them together 



