Diseases. 153 



action of the brain, and a temporary loss of sensation, volition, 

 and the other faculties, of which the brain is the organ. It 

 is sometimes caused in the case of nervous birds by the sudden 

 appearance of a cat or dog, or anything which may produce 

 fear or fright ; or it may proceed from a mechanical ob- 

 struction to the circulation, arising from organic affection of 

 the heart or of the vessels in its vicinity. When a bird is 

 observed to have a fit of this kind, remove it from the cage 

 and dash cold water upon it, and if you have any spirit of 

 ammonia in the house sprinkle a few drops on a pocket- 

 handkerchief and put it lightly over the head of the bird; 

 sometimes the attack proves fatal. I remember a gentleman 

 once coming into my bird-room with a white hat on; he came 

 suddenly forward to admire a Scotch fancy bird, a gem, which 

 had won me several prizes in the best of company. The bird 

 made an involuntary dash forward, and dropped to the bottom 

 of the cage, and, despite my efforts to revive him, he died. 

 He was a very nervous, timid bird. 



T. 



TUMOURS. Tumours, or wens, are divided into two classes, 

 i.e., solid and encysted ; simple or benign, or malignant. Birds 

 are sometimes, but not frequently, affected with these ex- 

 traneous growths about their heads, and they are mostly of 

 that kind known as encysted tumours, and commence their 

 growth at the base of the bill, and occasionally, but rarely, 

 at the back or side of the head. These latter are in most 

 cases what are known as solid tumours, and are always longer 

 in maturing. 



The solid tumour is generally enveloped in a dense cellular 

 sheath. This covering separates the diseased from the healthy 

 parts, whilst the cyst or encysted tumours, on the contrary, 

 must be considered as an integral part of the tumour, for 

 should any part of the cyst be left the disease is sure to be 

 reproduced. 



The principal forms of simple solid tumour are those termed 

 adipose or fatty, the fibrous, exostosis, or bony tumour. The 



