upon its withdrawal a small qiiautity i)f air passed out through the 

 right nostril, and blood passed from the nostrils into the pharynx, 

 leading us to the erroneous conclusion that we had encountered a 

 neoplasm and had passed the sound alongside between it and the 

 bony walls of the posterior naris. 



We were unable to learn the form, character, size, or attach- 

 ments of the obstruction ; concluded that a successful operation was 

 impossible, and abandoned further attempts at surgical interference. 



It was noticed that the patient now forced some air through the 

 right nostril, and continued to do so ; but its significance was not un- 

 derstood, and believing restoration of the animal to usefulness im- 

 possible, she was destroyed on November 26th and an autopsy made 



No neophism was found, but across the right posterior naris, 

 continuous with the nasal mucosa on the outer and the pharyngeal 

 mucosa on the inner side, was a thin, hymen-like membrane, stretch- 

 ing like a drum-head between the palatine, ethmoid, and vomer 

 bones, completely occluding the opening except for a small rent in 

 its centre, oval in form, three-fourths by one-half inch in diam- 

 eter, the result of the accidental opening made with the sound at 

 the time of our exploratory operation. The occluded right poste- 

 rior naris measured transversely from vomer to palatine bone seven- 

 eighths of an inch, while the left measured one and one-half inches. 

 The tissues were all healthy and showed no evidence of pre-existing 

 disease of any kind, indicating clearly that the abnormality was 

 congenital. 



The cause of the deformity must be referred to early emliryonie 

 life after the endoderm of the ovum had, by infolding, produced 

 the primitive intestine, ending anteriorly in the pharynx, in front 

 of which the olfactory pits develop, but are for a time separated 

 from the pharynx by a thin septum, which, becoming obliterated, 

 brings about the opening known as the posterior naris. 



In this individual the septum had become obliterated on the left 

 side, while on the right the development had become arrested, the 

 septum, as a result, persisting. 



The bibliorjraphy relating to this form of arrested development 

 is exceedingly limited. 



Through the aid of my colleague. Dr. Law, I have been enabled 

 to find the record of one similar case by Prof. Gamgee (0(«- Domestic 

 Animals in HeaJth and Disease, p. 622), who relates an instance 

 observed by Hering in 1842, in which a filly, two and one-half 

 years old, was presented to Prof. Hering f<ir advice regarding a 

 severe dyspnoja and roaring, which had been observed for a year. 



