Observations on the period of gestation in white mice

✍ Scribed by Daniel, J. Frank

• Publisher: John Wiley and Sons
• Year: 1910
• Tongue: English
• Weight: 265 KB
• Volume: 9
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1400090407

✦ Synopsis

Preliminary to a study which I am making on whitemice, I have found it necessary to reriamine in detail their period of gestation.

In this examination I have ascertained facts which, so far as I am aware, have not been previously described.

The general statement that the period of gestation in white mice is 21 days,' needs considerable modification. Such may be the case, but the likelihood is against it. I n fact it may be said that no unqualified statement can be made as to a definite period of gestation for all mice-since this period depends upon the state of the individual mouse.

My plan of study, which has consisted of isolating the fema.le immediately upon an observed copulation, and of keeping her apart from the male until the birth of her young-has been greatly facilitated by the use of observation cases of glass, in which the mice were kept under almost constant attention during the entire period of gestation.2 Under this condition, by observing the moment of copulation and the time of birth, I have been able to determine in many cases the period correct to the hour.

* Strictly speaking, the period of gestation is that interval of time elapsing between the act of fertilization and birth. In this paper it will be noted however, that I have used the term rather broadly to cover the period between the act of copulation and birth.