152 THE PATHOLOGY Otf THE TEETH. 



is such a close resemblance between the symptomatic 

 expressions of the nose following caries of these teeth 

 and chronic glanders, that error and confusion are 

 common. It is therefore highly important to distin- 

 guish these diseases, so essentially different in their 

 causes and effects. 



" When the membrane lining the sinuses has become 

 diseased, followed by the secretion of pus and polypus 

 growths, a jettage is established at one side of the nose. 

 It is white, lumpy, and abundant, and is augmented 

 in quantity by exercise. The lymphatic ganglions be- 

 come engorged and hard, but remain indolent, and 

 generally roll under the finger. The zygomatic tables 

 of the upper part of the superior maxillary and nasal 

 bones swell at the region of the affected sinuses, and 

 give a dull sound to percussion.* 



* Prof. Varnell says : " I am not aware that any animal suffers 

 from diseases of the sinuses of the head to the same extent as 

 the horse. The sinuses differ in size in different breeds, and in 

 individual horses of the same breed. I need scarcely point out 

 the necessity of bearing this fact in mind in forming diagnoses 

 of obscure diseases in this region of the head. In certain cases 

 it is not only important to ascertain whether the sinuses contain 

 anything abnormal, but also the nature and extent of the mor- 

 bific matter. Percussion with the ends of the fingers is one 

 mode of obtaining this information. Both sides of the head 

 should be struck, and the sound produced in one part compared 

 with that in another, and with what it is in health. I would 

 recommend students to become familiar with these various 

 sounds. They will be found to differ, according to the magni- 

 tude of the sinuses, in the same way that a large empty cask, 

 when struck, will differ in sound from a small one. It will also 

 be well to educate the ear to the character of the sounds pro- 

 duced by percussing the sinuses in differently formed heads. 

 * * * The sinuses, strictly speaking, are air cavities, 

 which communicate freely with each other, and by means of a 



