46 Tin: LUNG PLAGUE OF CATTLE. 



diarrhea in which the food is parsed in an undigested condition. If the effusion into 

 the lungs or chest is very extensive the pallor of the, month, eyelids, vulva, and skin 

 betrays the weak, bloodless condition. The tongue is furred and the breath of a heavy, 

 feverish, mawkish odor, but rarely fetid. Abortion is a common result in pregnant 

 cows. 



( ( >l ItSE. TERMINATION. 



In summer, when the disease shows its greatest violence, the mortality is not only 

 high, but early. Cattle will die after a few days' illness from the great prostration 

 attendant on the euomions effusion into the organs of the chest, the impairment of 

 breathing and the impairment or suspension of the vital functions in general. Others 

 die from early distension of the paunch with gas. In others, still, the profuse scouring 

 helps to speedily wear outtlie vital powers. In severe cases, that survive, for some time, 

 the rapid loss of flesh is most surprising. A loss of one-third of the w r eight in a single 

 week is by no means uncommon, and even one-half may be parted with in the same 

 length of time in extreme cases. 



In fatal cases, with a moderately rapid course, all the symptoms become more in- 

 tense fo several weeks; the pulse becomes more and more small, weak, and accele- 

 rated, and finally imperceptible; the breathing becomes rapid and difficult ; the mu- 

 cous membranes of the mouth, eyes, &c., become pale and bloodless; emaciation goes 

 on with active strides, and death ensues in from two to six weeks. 



In other cases, and especially in cold and dry weather, a portion of dead lung may 

 remain encysted in the chest, submitting to slow liquefaction and removal, and such 

 animals will go on for months doing badly, only to sink at last into such a state of 

 debility that death ensues from exhaustion and weakness. 



In others still, the retention of such diseased masses and the consequent debility, 

 determines the appearance of consumption (tuberculosis), which cuts off the animal. " 



Purulent infection and rupture of abscesses into the chest are other causes of death 

 in this disease. 



In cases about to recover, the symptoms gradually subside, life and appetite are 

 reacquired, and a more or less rapid recovery takes place. In the most favorable the 

 exudations are slowly reabsorbed, and the lung may be restored to its natural state. 

 In others, the exudation, which is mostly in the iuterlobular tissue, becomes in part 

 organized into fibrous material which, in contracting, compresses the lobules of lung 

 tissue, lessening their capacity for dilation, and leaving the animal short-winded and 

 predisposed to emphysema and other lung troubles. If kept quiet, such convalescents 

 fatten rapidly. 



Far more frequently, in this country at least, a mass of lung is entirely lost, being 

 divested of its vitality, inclosed in a fibrous cyst, and slowly liquefied and absorbed 

 through a course of several months. These continue to do poorly for a number of 

 months, and may yet entirely recover, the whole dead mass having been finally re- 

 moved and the sac having contracted into a dense fibrous structure. Even in this 

 case if the patient has been able to bear up under the continued drain, and has escaped 

 consumption and other risks, it may finally be successfully fattened. 



APPEARANCES OF THE CHEST AND LUNGS AFTER DEATH. 



If the disease is seen in its earliest stages, the changes are altogether confined to 

 the tissue of the lung. From the examination of the lungs of several hundred diseased 

 animals, I can confidently affirm that the implication of the serous covering of the 

 lung (pleura) is a secondary result. In all the most recent cases we find the lung 

 substance involved and the pleura sound, while in no one instance has the pleura been 

 found diseased to the exclusion of the lung tissue, or without an amount and character 

 of lung disease which implied priority of occurrence for that. Yet in all violent at- 

 tacks the disease will have proceeded far enough to secure implication of the pleura 

 as well, and hence we may describe the changes in t>he order in which they are usually 

 seen when the chest is opened. 



The cavity of the chest usually contains a quantity of liquid varying from one or 

 two pints to several gallons; sometimes yellowish, clear, and transparent ; at others, 

 slightly greenish, brownish- white, and opaque, or even exceptionally slightly colored 

 with blood. This effusion contains cell forms and grannies, and gelatinizes more or 

 less perfectly when exposed to the air. 



On the surface of the diseased lung and to a less extent on the inner side of the ribs 

 is a fibrinous deposit (false membrane), varying from the merest rough pellicle to a 

 mass of half an inch in thickness, and in the worst cases firmly binding the entire lung 

 to the inner side of the chest and to the diaphragm. These false membranes are 

 usually of an opaque white, though sometimes tinged with yellow, and in the deeper 

 layers even blood-stained, especially over an iafarcted lung. A noticeable feature 

 of these false membranes and one that serves to distinguish them from those of ordi- 

 nary pleurisy is that they are commonly limited to the surface of the diseased portion 



