SINCE my experiences in Blackwell's Island Insane Asylum were published in the World I have received hundreds of letters in regard to it. The edition containing my story long since ran out, and I have been prevailed upon to allow it to be published in book form, to satisfy the hundreds who are yet asking for copies.   I am happy to be able to state as a result of my visit to the asylum and the exposures consequent thereon, that the City of New York has appropriated $1,000,000 more per annum than ever before for the care of the insane. So I have at least the satisfaction of knowing that the poor unfortunates will be the better cared for because of my work.