ASTHMA. 79 



is then often mistaken for a bone in the throat, or for sponge 

 having" been desig'nedly given. The cough is now excited 

 by every change of temperature, food, or position ; until, at 

 length, it is almost incessant, and even sleep is interrupted 

 by it. In these latter stages the breathing becomes aifected ; 

 sometimes it is very laborious and painful. The irritation of 

 the cough frequently excites nausea and sickness, but nothing 

 is brought up but a little frothy mucus, which does not 

 come from the stomach, as is supposed, but from the bronchial 

 passages, where its presence forms the source of the irrita- 

 tion. When the disease is fully formed, its further progress 

 is quicker or slower as the exciting causes are continued or 

 discontinued. The modes in which it produces its fatal ter- 

 mination are also various. 



In some cases, the irritation of the cough, and the accom- 

 panying hectic, emaciates and wears down the animal to a 

 skeleton. In others, the congestion within the chest stops 

 respiration, and kills by a sudden suffocation ; or the obstruc- 

 tion the blood meets with in its passage through the heart 

 occasions accumulation in the head, and convulsive fits are 

 the precursors of death. Now and then a rupture of the 

 heart, or of some large blood-vessel, suddenly destroys : but 

 by far the most common termination of the complaint is in 

 dropsy, or serous collections within the chest or belly, or 

 both, but most frequently of the latter. In these cases, the 

 limbs and external parts of the body waste, but the belly 

 increases in its size ; the hair stares ; the breathing becomes 

 most laborious ; and, in the end, suffocation ensues. 



The morbid appearances, on dissection, are not always the 

 same ; but it may be remarked, that some disorganization is 

 always apparent. In the majority of cases, the visceral 

 marks of disease are very considerable. In some few, a rup- 

 ture of the air cells, very similar to what occurs in some 

 broken-winded horses, is apparent; in which cases, the air 

 extravasating through the parenchymatous substance of the 

 lungs, an emphysematous appearance takes place, and they 

 slightly crepitate under the touch. In some cases, serum has 



