Statements in regard to the effect of castration on poultry go back, it appears, to Aristotle. Yarrel in 1811 and again in 1850 has given an excellent account of many of the effects produced. His account of the effects on the cock seem to be based partly on hearsay, and while they contain much accurate information, yet the statement that the plumage of the capon is intermediate between that of the cock and hen is incorrect. The further statement that by cutting the oviduct the hen assumes the plumage of the capon has been shown by Sellheim to be erroneous. The operation referred to by Yarrel must have been one in which the ovary was removed.
Yarrel described a female pheasant that had assumed some of the characteristic colors of the male. On dissection he found that the ovary was diseased as well as the oviduct. He correctly assigns the change in plumage to the condition of the ovary. He states furthermore that most of the female pheasants that he had examined that had male plumage had not assumed the complete coloration of the male. In one case, however, a complete change had taken place. The change in pheasants he thought was due to old age accompanied by partial or complete loss of function of the ovary. For poultry he states:
“In the imperfect female the comb increases; a short spur or spurs appear; the plumage undergoes an alteration, getting what is usually called ‘foul-feathered;’ she ceases to produce any eggs, and makes an imperfect attempt to imitate the crow of the cock. Being profitless in this state, she is usually made away with. The proverb says:
A whistling woman and a crowing hen
Are neither good for gods nor men.
Our neighbors and allies the French, who seem to take a wider range in their prejudice against habits which they consider irregular, have the following proverb, which says:
Poule qui chante, Prêtre qui danse
Et Femme qui parle latin,
N’arrivent jamais à belle fin.
“I have seen two instances in which females of the wild duck have assumed to a considerable extent the appearance of the plumage of the mallard, even to the curled feathers of the tail. One of these birds, in my own collection, was given me when alive by my kind friend the late John Morgan, esq. When this bird was examined after death, the sexual organs were found to be diseased, as in the case of the hen pheasants referred to, and figured in the 2d volume of the History of our British Birds. In the published illustrations to his Fauna of Scandinavia, M. Nilsson has given a colored figure of a duck in this state of plumage (plate 163), which is called a barren female, and in which the curled tail-feathers are made very conspicuous.
“From the general similarity in these females to the appearance assumed for a time by healthy males in July, I am disposed to refer this seasonal change in males, in this and in other species of ducks, to a temporary exhausted state of the male generative organs, and their consequent diminished constitutional influence on the plumage.
“A male shut up by himself from early spring to the end of July undergoes no change in his plumage; but if he is allowed to associate with females till their season of incubation commences, he then goes through the change, and this appears to indicate the cause of the partial summer moulting.
“The appearance is somewhat different, but yet very interesting in insects and crustacea. In these classes the sexual organs are double and distinct, arranged one on each side of the elongated mesial line. It sometimes happens, that a species in which the sexes are of a different color, or markings, or form has one sexual organ of each sort, male and female, in which case each half of the same insect is developed under the exclusive influence of the sexual organ on its own side. Instances are preserved among our collections of butterflies, mothes and beetles; and I have seen it twice in the common lobster.