A despatch from Boston (says the Baltimore Cor- i e respondent of the Union,) announces that iijformar I -t tion has been received from Canada of the safe arri- I tt vql of tl?e fugitive slave Shadrack in that frozen xpr ; jc gion, where it is said that a large number of fugitives are ii) 9 condition bordering on starvation.'The owner of Shabrack, it is stated, has known his wherer aboqts if) Boston for some time, and merely had him arr.ested to test the questiou whether a fugitive oould be reclaimed from Boston.tiIiahlt;66e\dlt;