DISTENTION BY AIB. 145 



lias been frequently observed in the female of the domestic 

 fowlj and it is not even confined to gallinaceous birds, being 

 not unfrequent in the domestic duck. That disease of the 

 ovary should cause the formation of feathers totally distinct, 

 not only in colour, but in form, from those previously pro- 

 duced (as is most conspicuously the case of the tippet of the 

 Golden, or tail of the Silver Pheasant) is a very remarkable 

 circumstance, and one that has not yet received a satisfactory 

 physiological explanation. 



A correspondent writing to me from Argyllshire for- 

 warded the body of a young pheasant, in which the skin 

 was distended to an enormous extent with air. The cir- 

 cumference of the neck immediately behind the head was 

 5in., at the base of the neck 7in., and round the body 

 lOin. No other evidence of disease was perceptible on 

 post mortem examination. The bird, an early hatched 

 one, was in very good plumage, having already moulted 

 two of the primary wing feathers. My correspondent 

 stated that his keeper found several birds in the same con- 

 dition. The bird, when alive, was in the same bloated con- 

 dition as when forwarded. 



The case was not one of disease, but accident. Prom some 

 cause or other one of the air cavities which pervade to a 

 greater or less extent the bodies of all birds, and even extend 

 into the bones, had become ruptured, and the air during the 

 breathing of the bird had escaped under the skin, distending 

 it to the extent described. This rupture of an air cell might 

 have arisen spontaneously or from some injury. In either 

 case it was not necessarily fatal. If the keeper had made one 

 or two small punctures of the skin at different parts of the 

 body, the air would have escaped, and the bird in all 

 probability would have recovered; but it was so distended 

 that it could not even feed itself, and the crop and intestines, 

 although perfectly healthy, were destitute of food. Such 

 cases are not very uncommon, but, as they usually arise from 

 accident, it is remarkable that in this case several should have 



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