THE ORGANS OF RESPIRATION. 149 



many of the cases which have been recorded, the 

 existence of the tumours could be traced back for 

 two or more years prior to the period at which the 

 patient applied for medical advice, or before serious 

 complications presented themselves. The average 

 duration of these hydatids is from two to four years. 



Persons who are affected with hydatid cysts in 

 the cavity of the thorax do not experience any 

 functional derangement until the tumours have 

 attained to a large size ; and, until the later stages 

 of the disorder, the digestion, secretions, and pulse 

 continue natural, and there are no febrile symptoms, 

 although the sleep is disturbed, in consequence of the 

 embarrassment to the respiration. Pams, which are 

 acute, persistent, and subject to exacerbation, are 

 often felt in the side, or in the back, or at the epigas- 

 trium. The patient lays upon the back, or upon the 

 affected side. 



The most constant, and the most marked, symp- 

 tom is the difficulty of breathing, of which there are 

 frequent paroxysms, sometimes almost amounting to 

 suffocation ; there is also a dry cough, or only slight 

 expectoration. When the cyst has established a 

 communication with the bronchial tubes, the cough 

 is severe, and the expectoration becomes more abun- 

 dant. The matter which is expectorated is a serous, 

 puriform, or atheromatous fluid, containing fragments 

 of hydatids ; it may be either inodorous or fetid, or 

 may even have a gangrenous odour, according to the 

 state of the cyst, or of the part of the lung in which 

 the cyst is situated. The expectoration is occasionally 

 tinged with blood ; and, in some instances, the 

 hoemoptysis is very considerable. 



