SWANS 
POLISH SWANS. 
There is no doubt that the so-called Polish swans are 
sometimes produced from birds that are to all appearance 
the common mute swan {Cygnus olor). Many years ago, 
when at Cambridge, Professor N ewton called my attention 
to a pair of common swans that had bred, and the young 
birds were white when hatched, and continued to exhibit 
all the characteristics of Polish swans. This leads me to 
consider the subject of albinos, for it appears to me that 
we have several varieties of albino birds and other animals ; 
in the first place, the pure albino may be described as 
purely white with pink eyes, having no colouring pigment 
in its system. Now I find a great variety of these con- 
ditions. The so-called Himalayan rabbits have perfectly 
white bodies, but black legs, ears, nose, and tail ; at the 
same time, they have pink eyes. I also find perfectly 
white guinea-pigs with dark eyes. Among birds I find 
purely white jackdaws, blackbirds, Java sparrows, and 
other white finches with dark eyes. All these varieties I 
regard as semi-albinos. I have thus arrived at the con- 
clusion that the so-called ‘ Polish ’ swans belong to this 
group, and are semi-albinos, because they have the black 
marking round the base of the bill and the dark eyes of 
the common swan. 
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