TCO THE FARM DOCTOR. 



long, and S. Riifescens, of considerably greater length. The 

 calf, horse, ass, and mule have the Stivfigylus Micrurus of from 

 one and one-half to three inches long. The pig, the Strongylus 

 Elongatus of eight lines to one and one- half inches long. 

 Finally, the bird {Jien, turkey, pheasant, black stork, magpie, 

 hooded crow, green woodpecker, starli?ig, S7vift, etc.), have the 



Fig. 15. — Strongylus Filaria, male enlarged (Thudicum). When adult, should 

 be at least five times the length for this thickness. 



Syngamus Trachealis, male one-eighth inch, and female one- 

 half to five-eighths inch in length, always found united together, 

 so that the male appears like a process from the neck of the 

 female. 



The Strongyli in their mature condition inhabit the air 

 passages within the lungs, but they may be reproduced either 

 in or out of the body. In the first mode the female worm 

 creeps into an air cell and there encysts herself and produces 

 eggs or young worms already hatched, ot she dies, and the 

 myriad eggs hatching out amid the debris, the young worms 

 finally migrate into the adjacent air passages, grow to maturity, 

 and reproduce their kind. In the second mode the impreg- 

 nated female worm is expelled by coughing, and perishes in 

 water, or in moist earth, or on vegetables, and the eggs, escap- 

 ing from her decomposing remains, may lie unhatched for 

 months or even a year, or, in genial weather, may rapidly open 

 and allow the escape of the almost microscopic embryo worms. 

 These, in their turn, may live an indefinite length of time in 

 the water, or moist soil, or on vegetables, and only begin to 

 grow to their mature condition when taken in by a suitable host 

 with food or water. This is true of those of the sheep, goj.t, 

 and camel, of that of the ox, horse, and ass, and of that of the 



