i8o Veterinary Medicine. 



nux in small doses, or by weak currents of electricity. In meat 

 producing animals, it is often the best course to fatten rapidly, 

 or to turn over at once to the butcher. 



DII^ATATION OF THE CENTRAL CANAL OF THE 

 SPINAL CORD, syringomyelia! 



This means literally a cavity in the spinal cord but is applied 

 to cavities formed by dilatation of the central spinal canal, or by 

 an excavation in the nervous tissue immediately adjacent and 

 usually communicating with a dilated segment of the canal. In 

 man it is usually the result of an active proliferation of the 

 epithelial cells of the canal, blocking the same, or extending into 

 the adjacent nervous tissue in the form of a glioma. Indifferent 

 cases in dogs it occurred as the result of pressure. It has been 

 seen in dogs, cats and Guinea pigs, as a casual lesion and as the 

 result of experiment. 



In a case reported by Lienaux it extended for practically the 

 whole length of the cord, varying in form and size at different 

 points. In the lumbar portion it was only slightly dila'ted, in the 

 dorsal it was very irregular with prolongations into the gray mat- 

 ter, toward the cervical enlargement, its transverse section re- 

 sembled an inverted V, and in the anterior cervical part it was 

 unevenly rounded. Notable changes were cell proliferation and 

 subsequent degeneration with the formation of cavities, thicken- 

 ing of the neuroglia, and compression and even obliteration of 

 the vessels with circumscribed areas of necrosis, terminating also 

 in cavity formation. 



Symptoms. These vary with the nervous structures invaded, 

 atrophied or destroyed. Invasion of the anterior horns of gray 

 matter, causes trembling and muscular wasting. The implication 

 of the superior horns determines more or less marked anaesthesia. 

 Hypersesthesia, spasms, paresis and paraplegia are also seen but 

 no symptom nor group of symptoms is diagnostic of the exact 

 lesion. 



Treatment is manifestly, hopeless. 



