the Diseases in Poultry, 631 



elapse, when convulsions in the voluntary muscles appear, 

 and continue till life is exhausted. 



This disease is, I believe, always considered to be fatal; 

 but its nature and remote cause are, I apprehend, little known. 

 I believe, in most, if not all, cases, it is occasioned by some 

 vegetable poison, received into the stomach, which has the 

 effect of exciting an engorgement of the vessels of the brain, 

 and a consequent rupture of one of the veins or sinuses of 

 that organ. 



On the 31st of August, a fine young hen dropped from her 

 roost almost immediately after she had placed herself upon it. 

 The apoplectic symptoms, above described, were immediately 

 observed ; and, at the end of a week, convulsions of the 

 extremities, and of one or both of the larynges (or vocal 

 organs), took place ; and, on the eighth day, she died. She 

 was artificially fed and kept warm during the whole illness, 

 and deglutition w^as completely effected ; but the crop had 

 not discharged any of its contents, which had been thus 

 accumulated within it. 



On examining the head, I found a rupture of the longi- 

 tudinal vein or sinus near that part where in the human 

 subject the torcular Herophili is situated ; and a considerable 

 quantity of coagulated blood was lying in contact with the 

 cerebellum and medulla oblongata, and forced into the mas- 

 toid cells. The gizzard was distended with Irish ivij^ which 

 had been picked from a wall covered with it, and bounding 

 the poultry yard. On enquiry, I find that ivy is well known 

 to be poisonous to poultry. Its secondary operation on the 

 vascular system of the brain or cerebellum has probably 

 never been suspected. 



2. Emphysema. — Chickens, when about two weeks or 

 three weeks old, are subject to an emphysematous swelling, 

 a collection of air, under the integuments about the neck, 

 generally preceded by a slight morbid sound in the larynx; 

 and accompanied with vertigo, closing of the eyelids, droop- 

 ing or convulsive motion of the wings, and coldness of the 

 whole body, which ends in death. This is a different disease 

 from the roup^ which is designated by a mucous or muco- 

 purulent discharge from the eyelids, mouth, and nasal passages. 



Dissection presents no morbid appearance in the lungs, or 

 injury in the ribs ; and the pharynx, oesophagus, gizzard, and 

 the rest of the alimentary canal, are free from disease ; except 

 the ileum, the mucous coat of which I have, in some in- 

 stances, found in a state of softening (or what the French call 

 ramollissement\ readily admitting of abrasion, occasionally 

 attended with perforations; and, in one case, with black 



s s 4 



