I 20 
The Illustrated Book of Poultry. 
Having shown that the common slaty-blue dovecot pigeon is almost certainly the ancestor of all the 
varieties, he shows that many breeds when crossed are continually producing pigeons coloured more 
or less like it, and often identical in colour, though the breeds themselves have been kept pure 
beyond the memory of man. Similarly, many breeds of fowl when crossed continually produce 
the reddish-brown plumage of the Gallus Bankiva, which is by most naturalists now regarded as 
the ancient progenitor of our domestic breeds. Again, the White Aylesbury drake and a Black 
Labrador duck produced a bird coloured like the mallard. Similar instances are quoted in regard 
to cattle ; and in regard to the horse, reason having been given for the opinion that the original of 
all the equine races was some one animal striped like the zebra, it is shown that the produce of the 
horse and ass when crossed, and so extensively bred in Spain and America, have a strong tendency 
to develop stripes, especially on the legs. “ It would appear,” adds Mr. Darwin, “that with crossed 
animals a similar tendency to the recovery of lost characters holds good even with instincts, since 
so many cases have been recorded of the crossed offspring from two races, neither of which are 
incubators, becoming first-rate sitters, that the reappearance of this instinct must be attributed to 
reversion from crossing.”* 
The extent to which hereditary peculiarities may lie dormant in a strain, and be therefore 
capable of revival under this or any other stimulus, is one of the most surprising facts in physio- 
logical science, and still more occult manifestations of it have been specially remarked upon by 
Mr. Darwin, under the name of “ latent characters.” That eminent naturalist mentions as one of 
the most remarkable instances of this the Sebright Bantam. In this breed the sickles of the male 
bird have long been lost, and that peculiarity has now become so strongly established that even 
repeated crosses with the Black Bantam have little impaired it. Yet on the rare occasions in which 
a Sebright hen becomes barren, and, as then usually happens, begins to crow and assume other 
peculiarities of the male bird, she generally acquires full sickle feathers , showing that however long 
and entirely lost, some tendency to that characteristic male feature yet remains latent in the breed. 
We have endeavoured to explain this principle fully, because its immediate bearing upon the 
operations of the breeding-yard is most important. This we shall readily see by a few illustrations. 
There is, for instance, a well-known strain of Buff Cochins, of marked excellence in every point, but 
which has a strong tendency to breed a white feather in the cock’s tail. Now it is perfectly possible 
by a judicious cross from some other strain, and careful selection afterwards, to get rid of this 
objectionable feature ; and we will suppose an individual yard in which this has been so far 
accomplished that in only a small proportion does the hated white feather appear. This desired 
result, with a little care, will now be easily maintained while such a yard is bred to itself, or with 
any other not too far removed from it in blood ; but if crossed from a strain thoroughly distinct and 
alien, or what poultry-men call too “sudden” a cross (for without knowing the reason, they have 
found the evil of such often, and know it well), the old white feather may very probably reappear in 
all its original strength, though the new blood contained no tendency tc? it whatever. It is simply 
the cross of strange blood which gives the impulse to reversion. In the same way, to take the case 
mentioned just now, the pure white Spanish Dee being simply the result of assiduous breeding, and 
the most extreme care being needed for its preservation, the simple fact of crossing two entirely 
distinct strains gives the impulse to revert to the red face which belonged to the Minorca — in all 
probability the original breed from which it was derived. We need not illustrate this point further, 
as the same principle will readily explain many other anomalies which have long puzzled amateurs. 
* In Chapter IX. we gave another illustration of the same fact in the recovery of economic characteristics, but not carr'ed 
so far back. 
