64 DISEASES OF THE AIR-PASSAGES. 



Structure and origin. — Some pol3^pi have a fibrous or 

 almost cartilaginous structure, and others appear to be 

 composed of various little tumours agglutinated together. 

 They are formed originally under or within tlie membrane 

 by which the nasal cavity is lined ; but no better account 

 can be given of the cause of their appearance than that of 

 tumours in other parts of the body. 



Pedicle. — By some means, probably the increasing 

 weight of the tumour, and being in a dependent situation, 

 it is gradually detached from its base, and forces with it the 

 soft and easil}^ distensible membrane of the nose. As the 

 polypus continues to descend, this portion of membrane is 

 further elongated, and forms the pedicle or root of the 

 tumour : — a root it is not, for it is no continuation of the 

 substance of the tumour, but a mere duplicature of its in- 

 vesting membrane. How this may be witli regard to the 

 fungous bleeding polypus of the human subject, I am not 

 able to determine. The twisting of the pedicle, and tearing 

 it out by the root, may be a good practice wdth regard to 

 the human being, but cannot be justified where the pedicle 

 is a mere cord by which the polypus is suspended, and forms 

 no continuation or part of its substance. 



Shape. — The polypus, when it hangs free within the nasal 

 cavity, is usually of a pyriform or pear-like shape. It is 

 that form which it would naturally assume from the gradual 

 distension of the membrane, pressing on every side of the 

 tumour, and opposing its chief resistance at the base. 



Its aveight varies from a few drachms to three or four 

 pounds. 



Symptoms. — Some difficulty of breathing, apparently 

 arising from obstruction of some of the air-passages. A 

 discharge of mucus from one or both nostrils, sometimes 

 highly tinged with blood. Occasionally, pure blood runs 

 from the nose; and there is felt, by the hand placed before 

 the nostrils, an unequal rush of air from one or both of 

 them. Inspection in a full light, discloses, higher or lower 

 in the nostril, the rounded base of a polypus. 



Caution. — The veterinary surgeon must take care not 



