TRICHINIASIS
This disease is due to the introduction of the Trichina spiralis into the human body. The encysted worm is found embedded in the fibres of all the striped muscles of the trunk and limbs, and even in the heart, where it appears in the form of white ovoid bodies or capsules, the capsules being sometimes calcareous. The worm passes the greater part of its existence in the chrysalis state in the muscular system of one animal, and only reaches its mature condition in the stomach of another. Virchow and Zenker assert that the trichina not only frequently presents itself in the human organism, but that this organism is most favourable for its full development. Once in the stomach, the period of incubation is about three to eight days, and then propagation rapidly begins and continues, so that Dr. Kellen estimates that in about seven days after the ingestion of half a pound of meat the stomach and intestines may contain thirty millions of the worms. The worms when introduced into the stomach leave their capsules, become free, produce young, and these leave the stomach through its coats for the muscles, where they become encysted. The trichina is most frequently found in pork, seldom in sheep, horses, or oxen—the last being the most free.
Symptoms.—Intestinal irritation, loss of appetite, sickness, malaise, general weakness of the limbs, and diarrhœa. The eyelids swell as well as the joints, the skin is bathed in cold, clammy sweat, and a low form of fever sets in. Death may be due to peritonitis, paralysis of the muscles—the result of their destruction—or to irritative fever. During the perforation of the coats of the stomach and bowels by the worms, the mucous membrane becomes inflamed, pus is formed on the surface, and the stools become bloody.
TOXICOHÆMIC,
SNAKE POISONS, ETC.
Under this head may be classed all those effects produced by the sting or bite of various insects and reptiles, and also by the bite of the mad dog and wolf.
No medico-legal question is likely to be raised on this subject, at least in this country, where, with the exception of the common viper or adder, all our reptiles are harmless enough.
CHAPTER VII
THE VEGETABLE ALKALOIDS
Vegetable alkaloids may be classified in three groups: (1) derivatives of pyridine, e.g. atropine, conine; (2) derivatives of quinoline, e.g. cinchonine, narcotine; (3) substituted amines and amides. The majority of the vegetable alkaloids belong to the first two groups. They are for the most part solid, crystalline, and colourless; a few, such as conine, nicotine, and pilocarpin, are liquid. They combine with acids to form salts, and the salts are more soluble in water than the free alkaloid. Alkaloids possess certain properties in common, amongst which is that of being precipitated from their solutions by certain reagents, which are called alkaloidal grouping reagents. Some are precipitated by all the group reagents, others only by a few.