SEMIOLOGY. 11 



iu conjimction with tlio state of the pulse and cardiac action, 

 there is no source to which practical veterinary surgeons more 

 constantly appeal than the visible mucous membranes. 



From the character of the epithelium covering the schnei- 

 derian and conjunctival membranes, and the mode in which 

 the capillaries are disposed in the submucous layer, not only 

 is any fulness or turgescence of these vessels plainly visible, 

 but in many instances changes, physical as well as chemical, 

 which have occurred in the blood are laid out for our observa- 

 tion. The heightening in colour and increased vascularity 

 observed in the mucous membrane of the eyes and nasal 

 chambers from engorgement of the capillaries, whether the 

 direct result of arterial pressure or of venous obstruction, must 

 not in every case be accepted apart from other symptoms and 

 signs as infallibly indicative of inflammation. We are cer- 

 tainly, upon the whole, tolerably safe when we regard the 

 existence of this heightened colour and increased vascularity 

 as indicative of vascular excitement, and not unfrequently as 

 an early accompaniment of congestive and inflammatory action 

 in membranous structures, both of the serous and mucous 

 class. Marked injection of the conjunctival membrane is 

 probably rarely, or ever, absent in vascular excitement in con- 

 nection with the cerebral structures. 



When from derangement or structural changes in the liver, 

 the bile is either not elaborated from the blood, or, when 

 secreted, is in great part improperly disposed of, much of it 

 again in some form finding its way into the circulation, hoAV 

 rapidly and persistently do the mucous membranes of mouth, 

 nose, and eyes tell us of the disturbance, and continue to 

 maintain their peculiar yellow tinge as long as biliary com- 

 pounds remain in the blood, and while the diseased condition 

 of the liver continues. 



When from the operation or many causes the condition of 

 anwmia is established, a condition in which the sum-total of 

 the circulating blood is lessened, or the proper balance or 

 equilibrium which ought to exist amongst its several consti- 

 tuent elements is disturbed, early and satisfactory evidence is 

 afforded by the general bloodlessness of the more extensive 

 mucous membranes, and the curiously injected vessels of part 

 of the conjunctiva. 



