DISEASES OF RESPIRATORY PASSAGES AND ORuANS. 123 



to a moderate degree of heat, for the purpose of evaporaiion, a 

 grease spot remained ou the same ; hence it is an agent that should 

 never be used in pleurisy, nor in any disease occurring in the o" - 

 gans of respiration. Dropsical diseases, supervening on influenza, 

 are never benefited by cathartics, for they always lead to debility 

 and prostration. Influenza is a disease of very prostrating char- 

 acter; hence the proper plan of treatment is to sustain the vital 

 power, by nourishing diet, tonics, and stimulants — ginger and 

 golden seal. While commenting, however, on the linseed oil 

 treatment, I do not wish to censure the owner of the animal ; frr 

 I should be throwing stones into glass houses, having myself, in 

 furmer years, used and recommended this kind of oil for various 

 diseases ; but, after many mishaps, I am satisfied that it is unsafe 

 in the treatment of equine alFections. 



Pericarditis (Inflammation of PERicARDruM), 



(Sometimes called "Heart Disease.") 



The pericardium is a membranous sac, which surrounds and 

 incloses the heart. It is composed of two layers, united by eel- 

 hilar tissue. The external layer is dense and fibrous, and is 

 attached, by ligaments, to the sternum, or breast-bone and dia- 

 phragm, and above to the roots of the large blood-vessels. ^ The 

 internal layer exhibits internally a smooth surface, like the lining 

 membrane of the cavity of the chest. From this surflice is secreted 

 a serous fluid, which lubricates the heart, and protects it from the 

 friction which would otherwise occur. The pericardium is a wall 

 of defense for the heart, and keeps it in its proper position. 



Pericarditis signifies inflammation of the inner membrane of 

 the pericardium. It is a disease which is almost unknown to ibe 

 ordinary practitioner in this country, and entirely unknown to 

 the husbandman ; yet it is a disease that carries off a large number 

 of horses and cattle, and often the parties concerned in the treat- 

 ment and ownership of the animals do not even suspect the trua 

 nature of the malady. After the inflammatory action of the per- 

 icardium has reigned for several days, unsuspected and un- 

 checked, an inordinate eff"usion from the serous lining takes place. 

 We then have dropsy of the " hwu-t-bag." Water accuumlatefl 

 around the heart, which interferes with its action so as to put a 

 stop to circulation, and this results in the death of the animal. 

 P-v^irditb often accompanies, or is the sequel of, })leurisy and 



