

DISTENTION BY AIR. 153 



and other orders. That, disease of the ovary should cause 

 the formation of feathers totally distinct, not only in colour, 

 but in form, from those previously produced (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. (See Hamilton, P.Z.S., 1862, Feb. 11.) 



A similar change, but in the other direction, viz., that of a 

 cock assuming female plumage, has been recorded, but in 

 very rare instances. Mr. J. G. Millais mentions a case in the 

 Ibis of 1897; the Hon. Walter Rothschild has one in his 

 collection ; and three others, in which the change was very 

 marked, were exhibited by Dr. H. Hammond Smith at the 

 meeting of the Zoological Society, Feb. 11, 1911. In these 

 last cases the sexual organs showed no deviation from the 

 normal. 



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 

 oin., 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 

 condition. The bird, when alive, was in the same bloated 

 condition as when forwarded. 



The case was not one of disease, but accident. From 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 



