WORMS. 61 



the danger occurs. The migration of, literally, millions produces the 

 greatest suffering and causes a fever resembling, in some of its symptoms, 

 typhoid, and which not infrequently terminates fatally. If the victim, 

 however, have the strength to survive this migratory period until the 

 worms are encysted, he may entirely recover, notwithstanding the fact 

 that his muscles are filled with the worms. 



In this matter of parasitism, as in many others, an ounce of prevention 

 better than a pound of cure. If we eat our meat thoroughly cooked, 

 the chances of any parasites obtaining entrance to the human system are 

 reduced to a minimum. In the cases of trichinosis, for instance, investi- 

 gation has shown that the victims invariably have eaten pork raw, or in 

 a partially cooked condition. One of the worst epidemics of trichinosis 

 on record was one occurring in Saxony in 1884. All the cases were trace- 

 able to the flesh of one pig, and out of a total population of sixteen hundred, 

 three hundred and sixty-one were infected, and fifty-seven of these died 

 within one week. When trichina or any other parasite obtains entrance 

 to the body, no reliance should be placed in so-called vermifuges or quacks, 

 but a reputable physician should be called in at once. 



Another round worm is the so-called ' horse-hair snake,' which every- 

 one will tell you is a hair turned into a worm by soaking in water. The 

 writer was told this story when a boy, and he persistently soaked horse- 

 hairs for several weeks, but not a single worm was formed by the opera- 

 tion. It is hardly necessary to say that these hair-worms are really true 

 worms, and that they have not the remotest connection with the hair of 

 the horse. The fact that they are hair-like, frequently dark colored, and 

 often occur in water, is the sole cause of the myth. 



Scarcely less marvellous, however, is their history, so far 

 as known, but it must be said that concerning this, really but 

 little has yet been found out. According to the studies of 

 Dr. Leidy, a single specimen will produce over six million 

 eggs, which are laid in water, and soon hatch out the young, 

 which, as shown in the figure, differ extremely from the adult. 

 These larvaB, according to another observer, soon bore their way fig. go. — 



• ■ i • i • • 11 ii Embryo of 



into some aquatic insect, which m turn is swallowed by some hair-worm 

 fish, thus transferring the worm to a second host, where thev showing 

 pass through the remainder of their development, until at last tile hooks 



, . . - . around the 



tney escape into the water to lay their eggs. This account is anterior 

 good so far as it goes, but it fails to explain the frequent occur- 

 rence of these forms, fully grown, in insects which never go near the water. 

 A figure of the adult worm is hardly necessary ; it would be merely the 

 picture of a hair eight or nine inches long;. 



