448 DISEASES OF THE HORSE. 



calling it laminitis. The seat of greatest congestion will always 

 be foimd in the neighborhood of the toe. because of the increased 

 vascularity of that part. and. although at times it is limited to the 

 podophylloiis tissue alone, am^ or all parts of the keratogenous 

 membrane may be affected by the congestion and followed finally 

 by inflammation. 



Acute. — In the acute form of laminitis the symptoms may all de- 

 velop rapidly, or it may commence by the appearance of a little 

 soreness of the feet which in 24 or 48 hours develops into a well- 

 marked case. This peculiarity of development is due to one of two 

 causes. Either the congestion is general, but takes place slowly, 

 or it begins in one or more points and gradually spreads through- 

 out the laminjv. These acute cases generally run their course in 

 from one to two weeks. Usually a culmination of the symptoms 

 is reached, if the patient is properly treated, in from three to five 

 days; then evidences of recovery are discernible in favorable cases. 

 The lameness improA'es, the other symptoms gradually subside, and 

 eventually health is regained. It is in these cases that a strong 

 tendencv to disorganization of a destructive character exists: hence it 

 is we see so many recover imperfectly, with maiKed structural 

 changes permanently i-emaining. 



Suhacute. — Subacute laminitis is most often seen as a termination 

 of the acute form, although it may exist independent of or precede 

 an acute attack. It is characterized by the mildness of its symptoms, 

 slow course, and moderate tissue changes. It may be present a long 

 time before any pathological lesions result other than those found in 

 the acute form, and when these changes do take place they should 

 be viewed rather as complications. 



Chronic. — Chronic laminitis is a term used by many to designate 

 any of the sequelae of the acute and subacute forms of this disease. 

 Pure, chronic inflammation of the laminae is not very commonly met 

 uith, but is most frequent in horses that have long done fast track 

 \Aork. Thev have " fever in the feet " at all times and are continually 

 sore, both conditions being aggravated by work. Like chronic in- 

 flammation of other parts, there is a strong tendency to the develop- 

 ment of new connective tissue which, by its pi-essure upon the blood 

 vessels, interferes with nutrition. Wasting of the coffin bone and 

 inflammation of its covering with caries is not unusual. The con- 

 tinued fever and impaired function of secretion result in the produc- 

 tion of a horn deficient in elasticity, somewhat spongy in character, 

 and inclined to crumble. In some cases of " soreness " in horses used 

 to hard or fast work there is evident weakness of the coats of the 

 vessels, brought on bv repeated functional exhaustion. Here slight 

 work brings on congestion, Avhich results in serous effusion and 

 temi^orary symptoms similar to those of chronic laminitis. 



