632 Diseases i?i Poultry. 



marks on the peritoneal coat, opposite the disease in the 

 internal surface. These black marks, of which the annexed 

 is a representation, arise from a species of 

 disorganisation, which is, I believe, pecuhar to '^///// 

 serous membranes, as I have never observed l L L L L L 

 them in other structures; and, on that part 

 of the intestinal tube being immersed in water a few hours, 

 they disappear, and leave corresponding semiperforations. I 

 have remarked the same appearance in the human intestines, 

 accompanied with a softening and abrasion of the mucous 

 tunic, and a general disease of a specific character affecting 

 the whole serous covering of the abdominal viscera. The 

 other morbid phenomena consist of a softening, erosion, and 

 partial destruction of the spinal marrow, immediately adjoin- 

 ing the medulla oblongata, accompanied with a considerable 

 effusion of bloody serum, and preternatural vascularity of the 

 adjacent parts. 



The extravasation of air is probably produced by the rup- 

 ture of one of the axillary or thoracic air cells into which the 

 animal has the powder of inflating air from the lungs by means 

 of numerous large tubes resembling the respiratory organs of 

 insects. I am disposed to believe that there exists in these 

 cases a direct communication between the cellular membrane 

 infiltrated with air and the lungs ; because, whenever I have 

 punctured the integuments, and produced perfect collapse, 

 the swelling and crackling have been speedily and repeatedly 

 restored. I have not been able to trace the exact source 

 from which the air proceeds, as the cells, even in large birds, 

 are of delicate structure, and, in some, extend from the 

 axilla under the skin along the neck ; and, in young poultry, 

 they are still more delicate. I hope to be able to ascertain 

 this point, and to direct my enquiries more particularly to the 

 state of the trachea and inferior larynx. 



The morbid condition of the spinal medulla and the adjoin- 

 ing medullary structure is sufficient to account for the para- 

 lytic and convulsive affections of the upper extremities ; but 

 whether this state may be primary or secondary, appears to 

 me at present uncertain. As I am engaged in the in- 

 vestigation of some diseases of the nervous system, which has 

 led me to take advantage of comparative physiology and 

 pathology, I decline at present entering any farther into this 

 important subject. 



Bridgnorth^ Oct, \^, 1834. 



[In V. 207, 208. are figures and particulars of a species of 

 intestinal worm, of which numerous individuals had been found 



