OF VKTKRINARV MEDICINE. 231 



can be located, open up and let it escape. If practical, remove 

 all the dead bone. In necrosis of the bars of the mouth (the 

 lower jaw, it is not always necessary to operate except where the 

 parts are very sore and swollen. Then with a scalpel cut down 

 to the bone and this will allow the escape of the pus, if any, and 

 quicken the separation of the part if necrosed, and if not, it may 

 prevent it. Always cut down through the periosteum ; then let 

 alone until the pieces come out. Do not force them out or use 

 forceps. After they are removed, wash out with an antiseptic 

 solution three or four times a day. The patients usually make a 

 nice recovery. If the lesion is in the lower bars of the mouth, 

 when the patient is getting well, use the common jointed bit or 

 rubber covered chain. If the shafts of the long bones are af- 

 fected, make a large independent opening by trephining; remove 

 the sequestrum and wash out the cavity twice a day with anti- 

 septics. 



ATROPHY OF BONE. 



Atrophy of bone is an interstitial absorption of the bony 

 substance. This usually takes place in the cancellated portion 

 of the bone, but it may occur in the compact bone, which then 

 becomes softened and wastes away. It is not an inflammatory 

 process although it may start as such because of some injury. 

 In this condition the bone becomes diminished in size and weight 

 and if it happens in the bicipital groove, it allows the patella to 

 become dislocated very easily. 



This condition is incurable, though rational internal treat- 

 ment is in order, — such as iron, arsenic, etc. The disease usually 

 occurs in old animals. 



CONSTITUTIONAL OSTEOPOROSIS. 



Constitutional osteoporosis, or the big head, is a very pe- 

 culiar disease because it is little understood. The pathological 

 changes seem to be identical with those of localized osteo- 

 porosis. Some think that it is rheumatic, others that it is due 

 to a parasite and consequently infectious. It is often found in 



