71 



bronchi. During this passage, or while in the lungs, they pass 

 through the nympha stage and acquire sexual maturity. The 

 male and female then unite and attach themselves by their sucker- 

 like mouths to the mucous membrane of the trachea. Between 

 six and seven days are required from its entrance into the fowl 

 until its attachment to the trachea In about seven days more 

 the eggs within the body of the worm become mature. They 

 are coughed up into the mouth, swallowed by the fowl, and pass 

 through it into the soil. In about three weeks, the time varying 

 somewhat according to the temperature, these eggs, exposed to 

 the moisture and sun, hatch; the embryos are taken in their food 

 by the earthworm, where they remain until picked up by some 

 bird, when the above process is repeated. 



Some years one-half or two-thirds of the young fowls in cer- 

 tain localities are destroyed by this disease. This investigation 

 proves that if they were kept from eating infected earthworms, 

 that terrible scourge of poultry, the gapes, would be entirely 

 prevented. Not only this, but it serves as a key to unlock the 

 mysteries surrounding several other diseases, caused by parasites 

 belonging to this family; namely, the lung worm of calves 

 {Strongylus micrurus), the lung worm of hogs {Strongylus elonga- 

 tus), the lung worm of sheep {Strongylus filiaria), the grouse dis- 

 ease {Sfrongylus pergracilis). Great numbers of calves, hogs, 

 sheep and grouse, are yearly destroyed by these parasites. Their 

 original hosts have never been discovered. From certain 

 inquiries which I have made, I venture to predict that the earth- 

 worm will be found to be their original host.* 



* Since the above vvas first written I have found the embryo of Strongylus 

 micrzirus living in the earthworms of an infected pasture. 



