604 THE DISEASES OF THE HORSE 



CANKER 



Canker is goncrall}' an cxtcnsiim of tlic third form of thrusli, the fungus 

 spreading to the sensible sole, and afterwards to the colli n-bone itself. At 

 iirst the nn)rbid surface is concealed by the c»ld horn, but gradually this 

 breaks away, and then the extent of the mischief may be seen. A part or 

 the whole of the sole and the frog may be in a state of degeneration, gener- 

 ally depending upon the time during which the disease has been in existence, 

 and the care which has been taken of it, or the reverse. The only treatment 

 to be adopted is the careful removal of every loose piece of horn, so as to 

 expose the unsound surface to the action of remedies, and at the same time 

 to avoid poisoning it by the decomposing horn, which has a most irritating 

 effect. The sulphate of copper, and chloride of zinc, are the best applica- 

 tions, and they must be used in full strength. These cases, however, 

 require an experienced eye to enable the prescriber to judge of the proper 

 amount of caustic required ; and beyond suggesting the kind of remedy 

 required, no good can be done by written prescriptions. If it is impossible 

 to obtain the advice of a veterinarian, it will be better to begin by using a 

 mild caustic, and then increase the strength as it is found to be wanted. 

 Pitch ointment forms the best greasy application to the adjacent sound sur- 

 faces to protect them from the irritation of the discharge. 



LAMINITIS 



(Founder or Fever of the Feet) 



The term laminitis is now familiar with every one at all accustomed to 

 horses. The disease has been I'ccognizcd for many years under the terms 

 "founder " and " fever of the feet." It consists in an inflammation (which 

 may be acute or chronic) of the parts between the crust or wall and the 

 pedal-bone, including the laminse, whence the name by which it is now dis- 

 tinguished. These parts are supplied with a profusion of blood-vessels (see 

 page 504), and when inflammation is set up in them, the progress which it 

 makes is rapid, and the constitutional disturbance is unusually great, owing 

 probably to the want of space for the swelling which accompanies all inflam- 

 mations, and especially of vascular substances. The causes are either — 1st. 

 Localization of fever, whence the name " fever in the feet." 2nd. The 

 mechanical irritation of hard roads upon feet not accustomed to them ; and 

 3rd. Long confinement in a standing position on boai'd ship. L<aminitis is 

 also metastatic, making its ai>pearance very suddenly in a horse suffering 

 from quite another disease, as congestion of the lungs and in mares after 

 foaling, there being a peculiar sympathy between the feet and the mucous 

 membranes. When it is recollected that in our system of shoeing, the 

 laminje are made to support the whole weight of the body in consequence of 

 the shoe being in contact with the crust only, it can oidy occasion surprise 

 that this disease is not more frequent. Nature framed the horse's foot so 

 that an elastic pad should interpose between its back parts and the ground, 

 intending that the edge of the crust should take its share, but not all of the 



