A Forty-eight Hour Test for the Female Hormone with Capon Feathers as Indicator. ∗

Abstract

We have, as described elsewhere, obtained entirely female plumage in male brown leghorn fowls and capons by injections of female hormone prepared from human placenta, human pregnancy urine and from cow placenta.

The procedure consists in plucking definite areas and injecting the female hormone during the period of replacement which lasts about 3 to 4 weeks. The response of the feather could only be read in about a fortnight or more after plucking as this time is required for the feather germs to regenerate and pierce the sheath.

Since the feather changes are distinct and unmistakable we wished to make use of them as indicators of the female hormone. At the same time it was desirable to obtain readings in a short period of time and with small amounts of hormone. To this end the following method was developed: The breast feathers were used exclusively because their color is black in the male and salmon in the female, offering very distinct contrasts. Furthermore, the feathers in the breast regenerate more rapidly than in other regions of the body.

Breast feathers were plucked in similar regions, at the level of the shoulder, in a number of capons. The feathers were permitted to regenerate for 15 days. At the end of this time the young feathers were about 2.5 cm. in length. Each bird then received 6 cc. of a female hormone preparation containing by assay 100 rat units per cc. distributed in 4 simultaneous subcutaneous injections.

Forty-eight hours after the injections samples of the regenerating feathers were plucked. The sheath was slit, the inner pulp folded back with fine forceps and the feather itself spread out flat against a slide. The female, salmon, pigment deposited during the injection of the female hormone could be seen at once and with the naked eye at the base of the feathers in the majority of test birds.