Two hundred and eighty days, forty weeks, ten lunar months, or nine calendar months are here estimated as the usual duration of pregnancy (the actual computed average being 276-2/3 days). The exact day of conception (_not_ the fertile coition), can never be accurately determined; the only date from which conception can be dated, and the probable confinement day predicted with some chance of certainty, is the first day of the last menstrual flow, adding to this one week (seven days) for the average duration of the flow (with a few days lee-way). We count nine calendar months forward, and have the approximate date of the expected confinement. The most ready method is to add seven days to the first day of the last menstrual flow, count back three months, and add one year, when we have the future date when, or about when, delivery may be expected. An _exact_ estimate is but guess work; errors of one or two weeks either way may be made by the most experienced, as in cases where conception occurred shortly before the next menstrual period, which did not then appear. The present table is constructed on the above principle, the second column representing the day of quickening, nineteen weeks after the beginning of the last menstruation, with seven days added; and the third column still twenty weeks later. The date of quickening is still more variable than that of delivery, from one to four weeks. Intermediate dates may be fixed by adding the necessary number of days to each column. Thus, for Jan. 11th, the second column should read 31st of May, and the third column, October 18th, and so on. Beginning of last Quickening. Confinement. Menstruation. Jan. 1st.........May 20th.........Oct. 8th. Feb. 1st.........June 20th.........Nov. 8th. March 1st.........July 18th.........Dec. 4th. April 1st.........Aug. 18th.........Jan. 6th. May 1st.........Sept. 17th.........Feb. 5th. June 1st.........Oct. 8th.........March 8th. July 1st.........Nov. 17th.........April 7th. Aug. 1st.........Dec. 18th.........May 8th. Sept. 1st.........Jan. 18th.........June 6th. Oct. 1st.........Feb. 17th.........July 8th. Nov. 1st.........March 20th.........Aug. 8th. Dec. 1st.........April 19th.........Sept. 7th. ARTICLES FOR THE MOTHER'S USE.