In 1856 when Harris died Sibley became the librarian of Harvard. On 30 May 1866, Sibley married Charlotte Augusta Langdon Cook, at Sommerville, Massachusetts. Sibley oversaw both the physical and fiscal expansion of the Harvard Library. He also compiled the initial volumes of "Sibley's Harvard Graduates" series (three volumes published between 1873 and 1885 covering the classes of 1642 to 1689) and bequeathed funds to the Massachusetts Historical Society for continuation of this project. This task was undertaken by Clifford K. Shipton who covered the classes of 1690 to 1771 in 14 Volumes from 1932 to 1975, and in 1999 an 18th volume appeared covering classes from 1772 to 1774. Effects of estrogen on schizophrenia  Gender differences have been observed in the age of onset of schizophrenia. Women have a later age of onset and on average they are diagnosed 2 to 10 years later than men. In fact, the first onset of schizophrenia for men occurs around the ages of 20 to 25, while in women the first onset generally occurs between the ages of 25 to 30 years. However, it has also been noted that in women a second peak in schizophrenia occurs at the ages of 40 to 45. During this period there is a significant drop in estrogen levels in the body. These factors have led researchers to believe that estrogen may have an effect on psychosis in women. In support of the above mentioned conclusions many studies have been performed. Doctors Lindamer, Lohr, Harris, and Jeste conducted a study to determine age of onset of schizophrenia in which they examined gender differences in 194 patients ranging in age from 35 to 97. They found that the mean age for onset in men was 30, while in women it was 39. (It is important to note that this is just one study, and overall averages come from a combination of different studies). About 37% of the women developed schizophrenia at the age of 45, while only 16% of men reported the same. Thus, more women than men experience late onset schizophrenia. This indicates that there is indeed another peak for women at the age of 45 and women do develop schizophrenia later in life. Another study was conducted on older men and women to determine how schizophrenia affects them. The study consisted of 36 women and 86 men, all of similar age. More women than men were found to have paranoid schizophrenia and suffered more from severe positive symptoms rather than negative symptoms. All of this information is consistent with other studies showing that women have a later age of onset of schizophrenia and suffer more from severe positive symptoms rather than negative symptoms.