CORROSIVE OR IRRITANT POISONS 47 



thick and comparatively resistant coverings. The tongue on its upper 

 surface is protected with a dense membrane of epithelium, and the oeso- 

 phagus or gullet is likewise lined with a thick and tough membrane capable 

 of resisting puncture from such prickly or spinous plants as gorse and 

 comfrey. The fauces, being less guarded, more frecpjently suffer irritation, 

 and the bowels, with thinner and more highly vascular walls, are more 

 readily acted upon by poisons of the class we are considering. 



While the symptoms are the result of pain, the tissues are damaged or 

 destroyed by chemical action. 



Though our equine patient is not able to state in words the burning- 

 anguish he feels, there is a language of pain which it is the veterinarian's 

 business to learn. It has a large vocabulary, with many shades of meaning 

 to him who understands it by intimate association with the objects of his 

 solicitude. 



The common symptom — loss of appetite — will hardly be observed, as 

 poisons of this class are so rapid in their effects that the last meal may 

 have been partaken of in perfect health. 



Amongst the earliest symptoms are rigors and fidgetiness, staring coat, 

 colicky pains, evinced by stamping and scraping the feet, crouching and 

 looking round at the flank, trembling of the body and shaking of the tail, 

 sweating profusely over scattered patches, staggering, and either falling or 

 going down recklessly. The lips are sometimes swollen, and from between 

 them may issue great quantities of frothy saliva, which hangs in ropes from 

 the corners of the mouth. Inside, the tongue may also be swollen, the 

 lining membrane discoloured, the gums and mouth generally being of a 

 purple hue, with, in certain cases, patches of sloughing tissue and a most 

 offensive odour. The cavity seems filled with sticky mucus, and the 

 animal can with difficulty close his mouth owing to the swelling of the 

 tongue. 



The blood-shot eyes and anxious countenance bespeak intense pain and 

 fear. There is an agonized look of such intensity as is seldom observed as 

 the result of ordinary illness. Eespiration is hurried, nostrils dilated, the 

 pulse small and almost indistinct, the extremities having an icy coldness. 

 Vomition, so rare in the horse, is sometimes effected, the stomach contents 

 passing through the nostrils. The bowels may be either purged or consti- 

 pated, urine very high-coloured, and evacuated with groans. 



Such are the symptoms common to this group of poisons, but they vary 

 with the particular agent as well as in individuals. 



Some poisons declare themselves by their odour, as in carbolic acid, or 

 the lesions of the mouth may point to corrosive sublimate or a mineral acid 

 as the particular poison. 



