CANKER. 447 



it. In hot, foul, ill-ventilated stables this is found to be the 

 case. Let horses stand with their feet in the filth and muck of 

 uncleansed stables until they contract frushes, and let their 

 frushes go on unattended to, and canker will be the pretty cer- 

 tain result. This is one reason why the hind feet are more 

 subject to canker than the fore. Or, let horses remain during 

 the winter at straw-yard or in wet pasture, and, while their hoofs 

 are becoming frushy, abandon them altogether to " take their 

 chance," and canker will be sure to be the consequence. All this 

 would seem to shew, that the secretory apparatus of the foot may, 

 from continuance of such influences as heated and foul and im- 

 pure stabling, or simply from continued exposure to wet and dirt, 

 lose their power of producing sound horn, or indeed horny matter 

 at all, and in lieu thereof pour forth the matter peculiar to canker, 

 we call fungus. 



Notwithstanding canker may ordinarily originate under the 

 guise of frush, yet may it issue out of other local causes Grease, 

 from the matter trickling down over the heel into the cleft of 

 the frog, may give rise to disordered action of that part, which, 

 sooner or later, may end in the generation of canker. Quittor 

 likewise, it is said, may produce it; though this is an effect 

 I have had no evidence of myself. In a foot disposed to take 

 on cankerous action, there can be no doubt but that any lesion of 

 frog or sole may be followed by the disease. By far, however, 

 the most common origin of the disease is under the mask of frush. 



Pathology of Canker. — Close observation during life has 

 shewn, while post-mortem examination has confirmed the fact, 

 that the horn-producing — the keratogeneous — tissue is the part 

 specifically diseased in canker, and to this delicate tissue, and 

 its soft substrata, the cellular coverings of the frog and sole, 

 the disease is confined : neither bone, nor tendon, nor cartilage 

 being found implicated in its spread. On this part of my sub- 

 ject I rejoice to have an opportunity of deriving information 

 from a very interesting report obligingly made of a cankered 

 foot, which had been submitted to him by M. Bouley, by 

 M. Robin, Professor of the Faculty of Medicine at Paris, who, 

 with the aid of the microscope, found " that the anatomical 

 lesions in the tissue forming the horn bore, to appearance, no re- 



